libintl, iconv, gettext: account for libc provider and externals (#35450)

* libiconv can be provided by libc, so update packages which depend on
  libiconv to require the iconv virtual instead
* Many packages need special consideration when locating iconv depending
  on whether it is provided by libc (no prefix provided) or the libiconv
  package (in that case we want to provide a prefix)
* It was also noticed that when an iconv external was provided, that
  there was interference with linking (this should generally be handled
  by Spack's compiler wrappers and bears further investigation)
* Like iconv, libintl can be provided by libc or another package, namely
  gettext. It is not converted to a provider like libiconv because it
  provides additional routines. The logic is similar to that of iconv
  but instead of checking the provider, we check whether the gettext
  installation includes libintl.

39 files changed, 243 insertions, 127 deletions

diff --git a/var/spack/repos/builtin/packages/acl/package.py b/var/spack/repos/builtin/packages/acl/package.py
index 020400762e..1dbb16dfba 100644
--- a/var/spack/repos/builtin/packages/acl/package.py
+++ b/var/spack/repos/builtin/packages/acl/package.py
@@ -26,8 +26,10 @@ class Acl(AutotoolsPackage):
     depends_on("attr")
     depends_on("gettext")
 
-    def setup_build_environment(self, env):
-        env.append_flags("LDFLAGS", "-lintl")
+    def flag_handler(self, name, flags):
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
+            flags.append("-lintl")
+        return self.build_system_flags(name, flags)
 
     def autoreconf(self, spec, prefix):
         bash = which("bash")
diff --git a/var/spack/repos/builtin/packages/apex/package.py b/var/spack/repos/builtin/packages/apex/package.py
index a6f9c05563..f1590023bf 100644
--- a/var/spack/repos/builtin/packages/apex/package.py
+++ b/var/spack/repos/builtin/packages/apex/package.py
@@ -154,7 +154,8 @@ class Apex(CMakePackage):
             args.append("-DBFD_ROOT={0}".format(spec["binutils"].prefix))
 
         if "+binutils ^binutils+nls" in spec:
-            args.append("-DCMAKE_SHARED_LINKER_FLAGS=-lintl")
+            if "intl" in self.spec["gettext"].libs.names:
+                args.append("-DCMAKE_SHARED_LINKER_FLAGS=-lintl")
 
         if "+otf2" in spec:
             args.append("-DOTF2_ROOT={0}".format(spec["otf2"].prefix))
diff --git a/var/spack/repos/builtin/packages/bash/package.py b/var/spack/repos/builtin/packages/bash/package.py
index 69a8bc72e8..c772e16697 100644
--- a/var/spack/repos/builtin/packages/bash/package.py
+++ b/var/spack/repos/builtin/packages/bash/package.py
@@ -6,6 +6,7 @@
 import re
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Bash(AutotoolsPackage, GNUMirrorPackage):
@@ -177,8 +178,7 @@ class Bash(AutotoolsPackage, GNUMirrorPackage):
 
     def configure_args(self):
         spec = self.spec
-
-        return [
+        args = [
             # https://github.com/Homebrew/legacy-homebrew/pull/23234
             # https://trac.macports.org/ticket/40603
             "CFLAGS=-DSSH_SOURCE_BASHRC",
@@ -186,8 +186,12 @@ class Bash(AutotoolsPackage, GNUMirrorPackage):
             "--with-curses",
             "--enable-readline",
             "--with-installed-readline",
-            "--with-libiconv-prefix={0}".format(spec["iconv"].prefix),
         ]
+        if spec["iconv"].name == "libc":
+            args.append("--without-libiconv-prefix")
+        elif not is_system_path(spec["iconv"].prefix):
+            args.append("--with-libiconv-prefix={0}".format(spec["iconv"].prefix))
+        return args
 
     def check(self):
         make("tests")
diff --git a/var/spack/repos/builtin/packages/bcache/package.py b/var/spack/repos/builtin/packages/bcache/package.py
index 4f24bd9cd7..724e4dff19 100644
--- a/var/spack/repos/builtin/packages/bcache/package.py
+++ b/var/spack/repos/builtin/packages/bcache/package.py
@@ -24,16 +24,16 @@ class Bcache(MakefilePackage):
     depends_on("gettext")
     depends_on("pkgconfig", type="build")
 
-    def setup_build_environment(self, env):
-        # Add -lintl if provided by gettext, otherwise libintl is provided by the system's glibc:
-        if "gettext" in self.spec and "intl" in self.spec["gettext"].libs.names:
-            env.append_flags("LDFLAGS", "-lintl")
-
     patch(
         "func_crc64.patch",
         sha256="558b35cadab4f410ce8f87f0766424a429ca0611aa2fd247326ad10da115737d",
     )
 
+    def flag_handler(self, name, flags):
+        if name == "ldflags" and "intl" in self.spec["gettext"].libs.names:
+            flags.append("-lintl")
+        return self.env_flags(name, flags)
+
     def install(self, spec, prefix):
         mkdirp(prefix.bin)
         install("bcache-register", prefix.bin)
diff --git a/var/spack/repos/builtin/packages/bind9/package.py b/var/spack/repos/builtin/packages/bind9/package.py
index 8320fa3e59..68b1e9da44 100644
--- a/var/spack/repos/builtin/packages/bind9/package.py
+++ b/var/spack/repos/builtin/packages/bind9/package.py
@@ -19,7 +19,7 @@ class Bind9(AutotoolsPackage):
     depends_on("libuv", type="link")
     depends_on("pkgconfig", type="build")
     depends_on("openssl", type="link")
-    depends_on("libiconv", type="link")
+    depends_on("iconv", type="link")
 
     def configure_args(self):
         args = [
diff --git a/var/spack/repos/builtin/packages/binutils/package.py b/var/spack/repos/builtin/packages/binutils/package.py
index b3e3416701..cd11f0f8e5 100644
--- a/var/spack/repos/builtin/packages/binutils/package.py
+++ b/var/spack/repos/builtin/packages/binutils/package.py
@@ -269,9 +269,12 @@ class AutotoolsBuilder(spack.build_systems.autotools.AutotoolsBuilder):
         # also grab the headers from the bfd directory
         install(join_path(self.build_directory, "bfd", "*.h"), extradir)
 
-    def setup_build_environment(self, env):
-        if self.spec.satisfies("%cce"):
-            env.append_flags("LDFLAGS", "-Wl,-z,muldefs")
-
-        if "+nls" in self.spec:
-            env.append_flags("LDFLAGS", "-lintl")
+    def flag_handler(self, name, flags):
+        spec = self.spec
+        if name == "ldflags":
+            if spec.satisfies("%cce"):
+                flags.append("-Wl,-z,muldefs")
+        elif name == "ldlibs":
+            if "+nls" in self.spec and "intl" in self.spec["gettext"].libs.names:
+                flags.append("-lintl")
+        return self.build_system_flags(name, flags)
diff --git a/var/spack/repos/builtin/packages/elfutils/package.py b/var/spack/repos/builtin/packages/elfutils/package.py
index 53eab7b06e..4cec61c36e 100644
--- a/var/spack/repos/builtin/packages/elfutils/package.py
+++ b/var/spack/repos/builtin/packages/elfutils/package.py
@@ -7,6 +7,7 @@ import glob
 import os.path
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Elfutils(AutotoolsPackage, SourcewarePackage):
@@ -105,7 +106,12 @@ class Elfutils(AutotoolsPackage, SourcewarePackage):
         files = glob.glob(os.path.join("*", "Makefile.in"))
         filter_file("-Werror", "", *files)
 
-    flag_handler = AutotoolsPackage.build_system_flags
+    def flag_handler(self, name, flags):
+        if name == "ldlibs":
+            spec = self.spec
+            if "+nls" in spec and "intl" in spec["gettext"].libs.names:
+                flags.append("-lintl")
+        return self.inject_flags(name, flags)
 
     def configure_args(self):
         spec = self.spec
@@ -126,9 +132,19 @@ class Elfutils(AutotoolsPackage, SourcewarePackage):
         # zlib is required
         args.append("--with-zlib=%s" % spec["zlib"].prefix)
 
+        if spec.satisfies("@0.183:"):
+            if spec["iconv"].name == "libc":
+                args.append("--without-libiconv-prefix")
+            elif not is_system_path(spec["iconv"].prefix):
+                args.append("--with-libiconv-prefix=" + format(spec["iconv"].prefix))
+
         if "+nls" in spec:
-            # configure doesn't use LIBS correctly
-            args.append("LDFLAGS=-Wl,--no-as-needed -L%s -lintl" % spec["gettext"].prefix.lib)
+            # Prior to 0.183, only msgfmt is used from gettext.
+            if spec.satisfies("@0.183:"):
+                if "intl" not in spec["gettext"].libs.names:
+                    args.append("--without-libintl-prefix")
+                elif not is_system_path(spec["gettext"].prefix):
+                    args.append("--with-libintl-prefix=" + spec["gettext"].prefix)
         else:
             args.append("--disable-nls")
 
diff --git a/var/spack/repos/builtin/packages/extrae/package.py b/var/spack/repos/builtin/packages/extrae/package.py
index b645375605..eb646cc54f 100644
--- a/var/spack/repos/builtin/packages/extrae/package.py
+++ b/var/spack/repos/builtin/packages/extrae/package.py
@@ -127,14 +127,20 @@ class Extrae(AutotoolsPackage):
             make.add_default_arg("CXXFLAGS=%s" % self.compiler.cxx11_flag)
             args.append("CXXFLAGS=%s" % self.compiler.cxx11_flag)
 
+        return args
+
+    def flag_handler(self, name, flags):
         # This was added due to:
         # - configure failure
         # https://www.gnu.org/software/gettext/FAQ.html#integrating_undefined
         # - linking error
         # https://github.com/bsc-performance-tools/extrae/issues/57
-        args.append("LDFLAGS=-lintl -pthread")
-
-        return args
+        if name == "ldlibs":
+            if "intl" in self.spec["gettext"].libs.names:
+                flags.append("-lintl")
+        elif name == "ldflags":
+            flags.append("-pthread")
+        return self.build_system_flags(name, flags)
 
     def install(self, spec, prefix):
         with working_dir(self.build_directory):
diff --git a/var/spack/repos/builtin/packages/ffmpeg/package.py b/var/spack/repos/builtin/packages/ffmpeg/package.py
index 18f9a4558a..1c080fd088 100644
--- a/var/spack/repos/builtin/packages/ffmpeg/package.py
+++ b/var/spack/repos/builtin/packages/ffmpeg/package.py
@@ -75,7 +75,7 @@ class Ffmpeg(AutotoolsPackage):
     variant("libx264", default=False, description="H.264 encoding")
 
     depends_on("alsa-lib", when="platform=linux")
-    depends_on("libiconv")
+    depends_on("iconv")
     depends_on("yasm@1.2.0:")
     depends_on("zlib")
 
diff --git a/var/spack/repos/builtin/packages/fsl/package.py b/var/spack/repos/builtin/packages/fsl/package.py
index 2b7c92b430..add8cce02c 100644
--- a/var/spack/repos/builtin/packages/fsl/package.py
+++ b/var/spack/repos/builtin/packages/fsl/package.py
@@ -31,7 +31,7 @@ class Fsl(Package, CudaPackage):
     depends_on("expat")
     depends_on("libx11")
     depends_on("glu")
-    depends_on("libiconv")
+    depends_on("iconv")
     depends_on("openblas", when="@6:")
     depends_on("vtk@:8")
 
@@ -40,7 +40,7 @@ class Fsl(Package, CudaPackage):
 
     patch("build_log.patch")
     patch("eddy_Makefile.patch", when="@6.0.4")
-    patch("iconv.patch")
+    patch("iconv.patch", when="^libiconv")
     patch("fslpython_install_v5.patch", when="@:5")
     patch("fslpython_install_v604.patch", when="@6.0.4")
     patch("fslpython_install_v605.patch", when="@6.0.5")
diff --git a/var/spack/repos/builtin/packages/gdal/package.py b/var/spack/repos/builtin/packages/gdal/package.py
index 7e84f04181..b116dd8b62 100644
--- a/var/spack/repos/builtin/packages/gdal/package.py
+++ b/var/spack/repos/builtin/packages/gdal/package.py
@@ -9,7 +9,7 @@ import sys
 from spack.build_systems.autotools import AutotoolsBuilder
 from spack.build_systems.cmake import CMakeBuilder
 from spack.package import *
-from spack.util.environment import filter_system_paths
+from spack.util.environment import filter_system_paths, is_system_path
 
 
 class Gdal(CMakePackage, AutotoolsPackage, PythonExtension):
@@ -627,7 +627,6 @@ class AutotoolsBuilder(AutotoolsBuilder):
             self.with_or_without("hdf4", package="hdf"),
             self.with_or_without("hdf5", package="hdf5"),
             self.with_or_without("hdfs", package="hadoop"),
-            self.with_or_without("libiconv-prefix", variant="iconv", package="iconv"),
             self.with_or_without("idb", package="idb"),
             self.with_or_without("ingres", package="ingres"),
             self.with_or_without("jasper", package="jasper"),
@@ -681,6 +680,11 @@ class AutotoolsBuilder(AutotoolsBuilder):
             self.with_or_without("perl"),
             self.with_or_without("php"),
         ]
+        if "+iconv" in self.spec:
+            if self.spec["iconv"].name == "libc":
+                args.append("--without-libiconv-prefix")
+            elif not is_system_path(self.spec["iconv"].prefix):
+                args.append("--with-libiconv-prefix=" + self.spec["iconv"].prefix)
 
         # Renamed or modified flags
         if self.spec.satisfies("@3:"):
diff --git a/var/spack/repos/builtin/packages/gettext/package.py b/var/spack/repos/builtin/packages/gettext/package.py
index b7da6f97b8..4ae7eb59d9 100644
--- a/var/spack/repos/builtin/packages/gettext/package.py
+++ b/var/spack/repos/builtin/packages/gettext/package.py
@@ -6,6 +6,7 @@
 import re
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Gettext(AutotoolsPackage, GNUMirrorPackage):
@@ -78,7 +79,6 @@ class Gettext(AutotoolsPackage, GNUMirrorPackage):
         config_args = [
             "--disable-java",
             "--disable-csharp",
-            "--with-libiconv-prefix={0}".format(spec["iconv"].prefix),
             "--with-included-glib",
             "--with-included-gettext",
             "--with-included-libcroco",
@@ -87,6 +87,11 @@ class Gettext(AutotoolsPackage, GNUMirrorPackage):
             "--without-cvs",
         ]
 
+        if self.spec["iconv"].name == "libc":
+            config_args.append("--without-libiconv-prefix")
+        elif not is_system_path(self.spec["iconv"].prefix):
+            config_args.append("--with-libiconv-prefix=" + self.spec["iconv"].prefix)
+
         if "+curses" in spec:
             config_args.append("--with-ncurses-prefix={0}".format(spec["ncurses"].prefix))
         else:
diff --git a/var/spack/repos/builtin/packages/git/package.py b/var/spack/repos/builtin/packages/git/package.py
index 401af82d8f..dfca4fe6a2 100644
--- a/var/spack/repos/builtin/packages/git/package.py
+++ b/var/spack/repos/builtin/packages/git/package.py
@@ -7,6 +7,7 @@ import os
 import re
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Git(AutotoolsPackage):
@@ -466,12 +467,18 @@ class Git(AutotoolsPackage):
         # The test avoids failures when git is an external package.
         # In that case the node in the DAG gets truncated and git DOES NOT
         # have a gettext dependency.
-        if "+nls" in self.spec:
-            if "intl" in self.spec["gettext"].libs.names:
-                env.append_flags("EXTLIBS", "-L{0} -lintl".format(self.spec["gettext"].prefix.lib))
-            env.append_flags("CFLAGS", "-I{0}".format(self.spec["gettext"].prefix.include))
-
-        if "~perl" in self.spec:
+        spec = self.spec
+        if "+nls" in spec:
+            if "intl" in spec["gettext"].libs.names:
+                extlib_bits = []
+                if not is_system_path(spec["gettext"].prefix):
+                    extlib_bits.append(spec["gettext"].libs.search_flags)
+                extlib_bits.append("-lintl")
+                env.append_flags("EXTLIBS", " ".join(extlib_bits))
+            if not is_system_path(spec["gettext"].prefix):
+                env.append_flags("CFLAGS", spec["gettext"].headers.include_flags)
+
+        if "~perl" in spec:
             env.append_flags("NO_PERL", "1")
 
     def configure_args(self):
@@ -480,11 +487,17 @@ class Git(AutotoolsPackage):
         configure_args = [
             "--with-curl={0}".format(spec["curl"].prefix),
             "--with-expat={0}".format(spec["expat"].prefix),
-            "--with-iconv={0}".format(spec["iconv"].prefix),
             "--with-openssl={0}".format(spec["openssl"].prefix),
             "--with-zlib={0}".format(spec["zlib"].prefix),
         ]
 
+        if not self.spec["iconv"].name == "libc":
+            configure_args.append(
+                "--with-iconv={0}".format(
+                    "yes" if is_system_path(spec["iconv"].prefix) else spec["iconv"].prefix
+                )
+            )
+
         if "+perl" in self.spec:
             configure_args.append("--with-perl={0}".format(spec["perl"].command.path))
 
diff --git a/var/spack/repos/builtin/packages/glib/package.py b/var/spack/repos/builtin/packages/glib/package.py
index 730fb5e14e..5d53b74c25 100644
--- a/var/spack/repos/builtin/packages/glib/package.py
+++ b/var/spack/repos/builtin/packages/glib/package.py
@@ -6,6 +6,7 @@
 import os.path
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Glib(Package):
@@ -210,7 +211,7 @@ class Glib(Package):
         if self.spec.satisfies("@:2.72"):
             args.append("-Dgettext=external")
         if self.spec.satisfies("@:2.74"):
-            if "libc" in self.spec:
+            if self.spec["iconv"].name == "libc":
                 args.append("-Diconv=libc")
             else:
                 if self.spec.satisfies("@2.61.0:"):
@@ -244,7 +245,7 @@ class Glib(Package):
             args.append(
                 "--with-python={0}".format(os.path.basename(self.spec["python"].command.path))
             )
-        if "libc" in self.spec:
+        if self.spec["iconv"].name == "libc":
             args.append("--with-libiconv=maybe")
         else:
             args.append("--with-libiconv=gnu")
@@ -350,10 +351,14 @@ class Glib(Package):
         # Packages that link to glib were also picking up -lintl from glib's
         # glib-2.0.pc file. However, packages such as py-pygobject were
         # bypassing spack's compiler wrapper for linking and thus not finding
-        # the gettext library directory. The patch below explitly adds the
+        # the gettext library directory. The patch below explicitly adds the
         # appropriate -L path.
         spec = self.spec
-        if spec.satisfies("@2.0:2"):
+        if (
+            spec.satisfies("@2.0:2")
+            and "intl" in self.spec["gettext"].libs.names
+            and not is_system_path(spec["gettext"].prefix)
+        ):
             pattern = "Libs:"
             repl = "Libs: -L{0} -Wl,-rpath={0} ".format(spec["gettext"].libs.directories[0])
             myfile = join_path(self.spec["glib"].libs.directories[0], "pkgconfig", "glib-2.0.pc")
diff --git a/var/spack/repos/builtin/packages/gnupg/package.py b/var/spack/repos/builtin/packages/gnupg/package.py
index e206fb3dc1..ef989c7371 100644
--- a/var/spack/repos/builtin/packages/gnupg/package.py
+++ b/var/spack/repos/builtin/packages/gnupg/package.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Gnupg(AutotoolsPackage):
@@ -143,7 +144,6 @@ class Gnupg(AutotoolsPackage):
             "--disable-regex",
             "--with-zlib=" + self.spec["zlib"].prefix,
             "--without-tar",
-            "--without-libiconv-prefix",
             "--without-readline",
         ]
 
@@ -159,9 +159,12 @@ class Gnupg(AutotoolsPackage):
                     "--with-libassuan-prefix=" + self.spec["libassuan"].prefix,
                     "--with-ksba-prefix=" + self.spec["libksba"].prefix,
                     "--with-npth-prefix=" + self.spec["npth"].prefix,
-                    "--with-libiconv-prefix=" + self.spec["iconv"].prefix,
                 ]
             )
+            if self.spec["iconv"].name == "libc":
+                args.append("--without-libiconv-prefix")
+            elif not is_system_path(self.spec["iconv"].prefix):
+                args.append("--with-libiconv-prefix=" + self.spec["iconv"].prefix)
 
         if self.spec.satisfies("@:1"):
             args.extend(
diff --git a/var/spack/repos/builtin/packages/groff/package.py b/var/spack/repos/builtin/packages/groff/package.py
index 7fb2ffa999..132348295a 100644
--- a/var/spack/repos/builtin/packages/groff/package.py
+++ b/var/spack/repos/builtin/packages/groff/package.py
@@ -6,6 +6,7 @@
 import re
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Groff(AutotoolsPackage, GNUMirrorPackage):
@@ -77,7 +78,10 @@ class Groff(AutotoolsPackage, GNUMirrorPackage):
         args.extend(self.with_or_without("x"))
         if "@1.22.4:" in self.spec:
             args.extend(self.with_or_without("uchardet"))
-        args.append("--with-libiconv-prefix={0}".format(self.spec["iconv"].prefix))
+        if self.spec["iconv"].name == "libc":
+            args.append("--without-libiconv-prefix")
+        elif not is_system_path(self.spec["iconv"].prefix):
+            args.append("--with-libiconv-prefix={0}".format(self.spec["iconv"].prefix))
         return args
 
     def setup_run_environment(self, env):
diff --git a/var/spack/repos/builtin/packages/krb5/package.py b/var/spack/repos/builtin/packages/krb5/package.py
index 08e70deeb9..493b191490 100644
--- a/var/spack/repos/builtin/packages/krb5/package.py
+++ b/var/spack/repos/builtin/packages/krb5/package.py
@@ -81,10 +81,7 @@ class Krb5(AutotoolsPackage):
 
         return args
 
-    def setup_build_environment(self, env):
-        env.prepend_path("LD_LIBRARY_PATH", self.spec["gettext"].prefix.lib)
-
     def flag_handler(self, name, flags):
-        if name == "ldlibs":
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
             flags.append("-lintl")
-        return (flags, None, None)
+        return inject_flags(name, flags)
diff --git a/var/spack/repos/builtin/packages/lftp/package.py b/var/spack/repos/builtin/packages/lftp/package.py
index d6ee43a95e..6c8df1ad09 100644
--- a/var/spack/repos/builtin/packages/lftp/package.py
+++ b/var/spack/repos/builtin/packages/lftp/package.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Lftp(AutotoolsPackage):
@@ -19,6 +20,7 @@ class Lftp(AutotoolsPackage):
     version("4.6.4", sha256="791e783779d3d6b519d0c23155430b9785f2854023eb834c716f5ba78873b15a")
 
     depends_on("expat")
+    depends_on("gettext")
     depends_on("iconv")
     depends_on("ncurses")
     depends_on("openssl")
@@ -26,11 +28,20 @@ class Lftp(AutotoolsPackage):
     depends_on("zlib")
 
     def configure_args(self):
-        return [
+        args = [
             "--with-expat={0}".format(self.spec["expat"].prefix),
-            "--with-libiconv={0}".format(self.spec["iconv"].prefix),
             "--with-openssl={0}".format(self.spec["openssl"].prefix),
             "--with-readline={0}".format(self.spec["readline"].prefix),
             "--with-zlib={0}".format(self.spec["zlib"].prefix),
             "--disable-dependency-tracking",
         ]
+        if self.spec["iconv"].name == "libc":
+            args.append("--without-libiconv-prefix")
+        elif not is_system_path(self.spec["iconv"].prefix):
+            args.append("--with-libiconv-prefix={0}".format(self.spec["iconv"].prefix))
+        if "intl" not in self.spec["gettext"].libs.names:
+            args.append("--without-libintl-prefix")
+        elif not is_system_path(self.spec["gettext"].prefix):
+            args.append("--with-libintl-prefix={0}".format(self.spec["gettext"].prefix))
+
+        return args
diff --git a/var/spack/repos/builtin/packages/libarchive/package.py b/var/spack/repos/builtin/packages/libarchive/package.py
index 56b9d90f95..c86bf2f4d2 100644
--- a/var/spack/repos/builtin/packages/libarchive/package.py
+++ b/var/spack/repos/builtin/packages/libarchive/package.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Libarchive(AutotoolsPackage):
@@ -109,7 +110,7 @@ class Libarchive(AutotoolsPackage):
     depends_on("libxml2", when="xar=libxml2")
     depends_on("expat", when="xar=expat")
 
-    depends_on("libiconv", when="+iconv")
+    depends_on("iconv", when="+iconv")
 
     conflicts(
         "crypto=mbedtls", when="@:3.4.1", msg="mbed TLS is only supported from libarchive 3.4.2"
@@ -119,11 +120,19 @@ class Libarchive(AutotoolsPackage):
     # The build test suite cannot be built with Intel
 
     def configure_args(self):
+        spec = self.spec
         args = ["--without-libb2"]
         args += self.with_or_without("compression")
         args += self.with_or_without("crypto")
-        args += self.with_or_without("iconv")
         args += self.with_or_without("xar")
         args += self.enable_or_disable("programs")
 
+        if "+iconv" in spec:
+            if spec["iconv"].name == "libc":
+                args.append("--without-libiconv-prefix")
+            elif not is_system_path(spec["iconv"].prefix):
+                args.append("--with-libiconv-prefix={p}".format(p=spec["iconv"].prefix))
+        else:
+            args.append("--without-iconv")
+
         return args
diff --git a/var/spack/repos/builtin/packages/libxpm/package.py b/var/spack/repos/builtin/packages/libxpm/package.py
index 26e169e74f..e3f4f2ee35 100644
--- a/var/spack/repos/builtin/packages/libxpm/package.py
+++ b/var/spack/repos/builtin/packages/libxpm/package.py
@@ -26,9 +26,7 @@ class Libxpm(AutotoolsPackage, XorgPackage):
     depends_on("pkgconfig", type="build")
     depends_on("util-macros", type="build")
 
-    def setup_build_environment(self, env):
-        # If libxpm is installed as an external package, gettext won't
-        # be available in the spec. See
-        # https://github.com/spack/spack/issues/9149 for details.
-        if "gettext" in self.spec and "intl" in self.spec["gettext"].libs.names:
-            env.append_flags("LDFLAGS", "-lintl")
+    def flag_handler(self, name, flags):
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
+            flags.append("-lintl")
+        return env_flags(name, flags)
diff --git a/var/spack/repos/builtin/packages/mono/package.py b/var/spack/repos/builtin/packages/mono/package.py
index 606e023a55..7525b563a0 100644
--- a/var/spack/repos/builtin/packages/mono/package.py
+++ b/var/spack/repos/builtin/packages/mono/package.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Mono(AutotoolsPackage):
@@ -74,6 +75,8 @@ class Mono(AutotoolsPackage):
 
     def configure_args(self):
         args = []
-        li = self.spec["iconv"].prefix
-        args.append("--with-libiconv-prefix={p}".format(p=li))
+        if self.spec["iconv"].name == "libc":
+            args.append("--without-libiconv-prefix")
+        elif not is_system_path(self.spec["iconv"].prefix):
+            args.append("--with-libiconv-prefix={p}".format(p=self.spec["iconv"].prefix))
         return args
diff --git a/var/spack/repos/builtin/packages/neovim/package.py b/var/spack/repos/builtin/packages/neovim/package.py
index df14643c0d..c9276ce1f5 100644
--- a/var/spack/repos/builtin/packages/neovim/package.py
+++ b/var/spack/repos/builtin/packages/neovim/package.py
@@ -94,7 +94,7 @@ class Neovim(CMakePackage):
     depends_on("jemalloc", type="link", when="platform=linux")
     depends_on("lua-lpeg")
     depends_on("lua-mpack")
-    depends_on("libiconv", type="link")
+    depends_on("iconv", type="link")
     depends_on("libtermkey", type="link")
     depends_on("libuv", type="link")
     depends_on("libluv", type="link")
@@ -117,7 +117,7 @@ class Neovim(CMakePackage):
     with when("@0.6:"):
         depends_on("cmake@3.10:", type="build")
         depends_on("gperf@3.1:", type="link")
-        depends_on("libiconv@1.15:", type="link")
+        conflicts("libiconv@:1.14")
         depends_on("libtermkey@0.22:", type="link")
         depends_on("libvterm@0.1.4:", type="link")
         depends_on("msgpack-c@3.0.0:", type="link")
diff --git a/var/spack/repos/builtin/packages/nfs-utils/package.py b/var/spack/repos/builtin/packages/nfs-utils/package.py
index 1605dfe969..7a1744f147 100644
--- a/var/spack/repos/builtin/packages/nfs-utils/package.py
+++ b/var/spack/repos/builtin/packages/nfs-utils/package.py
@@ -29,9 +29,8 @@ class NfsUtils(AutotoolsPackage):
     depends_on("util-linux")
     depends_on("gettext")
 
-    def setup_build_environment(self, env):
-        env.append_flags("LIBS", "-lintl")
-
     def configure_args(self):
         args = ["--disable-gss", "--with-rpcgen=internal"]
+        if "intl" in self.spec["gettext"].libs.names:
+            args.append("LIBS=-lintl")
         return args
diff --git a/var/spack/repos/builtin/packages/oci-systemd-hook/package.py b/var/spack/repos/builtin/packages/oci-systemd-hook/package.py
index 1947e01cca..72d08ad7e3 100644
--- a/var/spack/repos/builtin/packages/oci-systemd-hook/package.py
+++ b/var/spack/repos/builtin/packages/oci-systemd-hook/package.py
@@ -27,9 +27,11 @@ class OciSystemdHook(AutotoolsPackage):
     depends_on("util-linux")
     depends_on("go-md2man")
 
-    def configure_args(self):
-        args = ["LDFLAGS=-lintl"]
-        return args
+    def flag_handler(self, name, flags):
+        if name == "ldlibs":
+            if "intl" in self.spec["gettext"].libs.names:
+                flags.append("-lintl")
+        return self.build_system_flags(name, flags)
 
     def install(self, spec, prefix):
         oci_systemd_hook_jsondir = "oci_systemd_hook_jsondir="
diff --git a/var/spack/repos/builtin/packages/opencv/package.py b/var/spack/repos/builtin/packages/opencv/package.py
index 03ac773771..c786183cd5 100644
--- a/var/spack/repos/builtin/packages/opencv/package.py
+++ b/var/spack/repos/builtin/packages/opencv/package.py
@@ -595,7 +595,7 @@ class Opencv(CMakePackage, CudaPackage):
     with when("+wechat_qrcode"):
         conflicts("~dnn")
         conflicts("~imgproc")
-        depends_on("libiconv")
+        depends_on("iconv")
 
     with when("+xfeatures2d"):
         with when("+cuda"):
diff --git a/var/spack/repos/builtin/packages/procps/package.py b/var/spack/repos/builtin/packages/procps/package.py
index fa06d5558c..5c135e2505 100644
--- a/var/spack/repos/builtin/packages/procps/package.py
+++ b/var/spack/repos/builtin/packages/procps/package.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Procps(AutotoolsPackage):
@@ -17,6 +18,8 @@ class Procps(AutotoolsPackage):
     version("master", branch="master")
     version("3.3.15", tag="v3.3.15")
 
+    variant("nls", default=True, description="Enable Native Language Support.")
+
     depends_on("autoconf", type="build")
     depends_on("automake", type="build")
     depends_on("libtool", type="build")
@@ -24,7 +27,7 @@ class Procps(AutotoolsPackage):
     depends_on("pkgconfig@0.9.0:", type="build")
     depends_on("dejagnu", type="test")
     depends_on("iconv")
-    depends_on("gettext")
+    depends_on("gettext", when="+nls")
     depends_on("ncurses")
 
     conflicts("platform=darwin", msg="procps is linux-only")
@@ -33,11 +36,29 @@ class Procps(AutotoolsPackage):
         sh = which("sh")
         sh("autogen.sh")
 
+    def flag_handler(self, name, flags):
+        if name == "ldlibs":
+            spec = self.spec
+            if "+nls" in spec and "intl" in spec["gettext"].libs.names:
+                flags.append("-lintl")
+        return self.build_system_flags(name, flags)
+
     def configure_args(self):
-        return [
-            "--with-libiconv-prefix={0}".format(self.spec["iconv"].prefix),
-            "--with-libintl-prefix={0}".format(self.spec["gettext"].prefix),
-            "--with-ncurses",
-            # Required to avoid libintl linking errors
-            "--disable-nls",
-        ]
+        spec = self.spec
+        args = ["--with-ncurses"]
+
+        if "+nls" in spec:
+            args.append("--enable-nls")
+            if "intl" not in spec["gettext"].libs.names:
+                args.append("--without-libintl-prefix")
+            elif not is_system_path(spec["gettext"].prefix):
+                args.append("--with-libintl-prefix=" + spec["gettext"].prefix)
+        else:
+            args.append("--disable-nls")
+
+        if spec["iconv"].name == "libc":
+            args.append("--without-libiconv-prefix")
+        elif not is_system_path(spec["iconv"].prefix):
+            args.append("--with-libiconv-prefix={0}".format(spec["iconv"].prefix))
+
+        return args
diff --git a/var/spack/repos/builtin/packages/pulseaudio/package.py b/var/spack/repos/builtin/packages/pulseaudio/package.py
index e975f2a30c..f96d2af990 100644
--- a/var/spack/repos/builtin/packages/pulseaudio/package.py
+++ b/var/spack/repos/builtin/packages/pulseaudio/package.py
@@ -37,7 +37,7 @@ class Pulseaudio(AutotoolsPackage):
     depends_on("gconf", when="+gconf")
     depends_on("json-c@0.11:")
     depends_on("libcap")
-    depends_on("libiconv")
+    depends_on("iconv")
     depends_on("libsndfile@1.0.18:")
     depends_on("libtool@2.4:")  # links to libltdl.so
     depends_on("libsm", when="+x11")
diff --git a/var/spack/repos/builtin/packages/py-onnxruntime/package.py b/var/spack/repos/builtin/packages/py-onnxruntime/package.py
index 7efd37f8ec..68929f6d3c 100644
--- a/var/spack/repos/builtin/packages/py-onnxruntime/package.py
+++ b/var/spack/repos/builtin/packages/py-onnxruntime/package.py
@@ -52,7 +52,7 @@ class PyOnnxruntime(CMakePackage, PythonExtension):
     # https://github.com/cms-externals/onnxruntime/compare/5bc92df...d594f80
     patch("cms.patch", level=1, when="@1.7.2")
     # https://github.com/cms-externals/onnxruntime/compare/0d9030e...7a6355a
-    patch("cms_1_10.patch", whe="@1.10")
+    patch("cms_1_10.patch", when="@1.10")
     # https://github.com/microsoft/onnxruntime/issues/4234#issuecomment-698077636
     # only needed when iconv is provided by libiconv
     patch("libiconv.patch", level=0, when="@1.7.2 ^libiconv")
diff --git a/var/spack/repos/builtin/packages/qt/package.py b/var/spack/repos/builtin/packages/qt/package.py
index 94e7734bef..c388adaca1 100644
--- a/var/spack/repos/builtin/packages/qt/package.py
+++ b/var/spack/repos/builtin/packages/qt/package.py
@@ -368,10 +368,11 @@ class Qt(Package):
     # webkit requires libintl (gettext), but does not test for it
     # correctly, so add it here.
     def flag_handler(self, name, flags):
-        if "+webkit" in self.spec and name == "ldlibs":
-            flags.append("-lintl")
-
-        return (flags, None, None)
+        if self.name == "ldlibs":
+            spec = self.spec
+            if "+webkit" in spec and "intl" in spec["gettext"].libs.names:
+                flags.append("-lintl")
+        return self.inject_flags(name, flags)
 
     @when("@4 platform=darwin")
     def patch(self):
diff --git a/var/spack/repos/builtin/packages/r-rjava/package.py b/var/spack/repos/builtin/packages/r-rjava/package.py
index 034dc19048..812d4daacb 100644
--- a/var/spack/repos/builtin/packages/r-rjava/package.py
+++ b/var/spack/repos/builtin/packages/r-rjava/package.py
@@ -27,7 +27,7 @@ class RRjava(RPackage):
     # these are not listed as dependencies but are needed
     depends_on("bzip2")
     depends_on("icu4c")
-    depends_on("libiconv")
+    depends_on("iconv")
     depends_on("pcre2")
     depends_on("xz")
     depends_on("zlib")
diff --git a/var/spack/repos/builtin/packages/rpcsvc-proto/package.py b/var/spack/repos/builtin/packages/rpcsvc-proto/package.py
index 98e498409f..85b7c208d3 100644
--- a/var/spack/repos/builtin/packages/rpcsvc-proto/package.py
+++ b/var/spack/repos/builtin/packages/rpcsvc-proto/package.py
@@ -20,7 +20,10 @@ class RpcsvcProto(AutotoolsPackage):
     depends_on("gettext")
 
     def configure_args(self):
-        return ["LIBS=-lintl"]
+        if "intl" in self.spec["gettext"].libs.names:
+            return ["LIBS=-lintl"]
+        else:
+            return []
 
     @run_before("build")
     def change_makefile(self):
diff --git a/var/spack/repos/builtin/packages/rrdtool/package.py b/var/spack/repos/builtin/packages/rrdtool/package.py
index f2d1cd7081..413024b47e 100644
--- a/var/spack/repos/builtin/packages/rrdtool/package.py
+++ b/var/spack/repos/builtin/packages/rrdtool/package.py
@@ -22,8 +22,9 @@ class Rrdtool(AutotoolsPackage):
     depends_on("perl-extutils-makemaker")
 
     def configure_args(self):
-        args = [
-            "LDFLAGS=-lintl",
-            "--with-systemdsystemunitdir=" + self.spec["rrdtool"].prefix.lib.systemd.system,
-        ]
-        return args
+        return ["--with-systemdsystemunitdir=" + self.spec["rrdtool"].prefix.lib.systemd.system]
+
+    def flag_handler(self, name, flags):
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
+            flags.append("-lintl")
+        return self.build_system_flags(name, flags)
diff --git a/var/spack/repos/builtin/packages/subversion/package.py b/var/spack/repos/builtin/packages/subversion/package.py
index 423d4c4e86..97be031546 100644
--- a/var/spack/repos/builtin/packages/subversion/package.py
+++ b/var/spack/repos/builtin/packages/subversion/package.py
@@ -6,6 +6,7 @@
 import re
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Subversion(AutotoolsPackage):
@@ -102,16 +103,14 @@ class Subversion(AutotoolsPackage):
             args.append("APXS=no")
 
         if "+nls" in spec:
-            args.extend(
-                [
-                    "LDFLAGS={0}".format(spec["gettext"].libs.search_flags),
-                    # Using .libs.link_flags is the canonical way to add these arguments,
-                    # but since libintl is much smaller than the rest and also the only
-                    # necessary one, we specify it by hand here.
-                    "LIBS=-lintl",
-                    "--enable-nls",
-                ]
-            )
+            args.append("--enable-nls")
+            if "intl" in spec["gettext"].libs.names:
+                # Using .libs.link_flags is the canonical way to add these arguments,
+                # but since libintl is much smaller than the rest and also the only
+                # necessary one, we would specify it by hand here
+                args.append("LIBS=-lintl")
+                if not is_system_path(spec["gettext"].prefix):
+                    args.append("LDFLAGS={0}".format(spec["gettext"].libs.search_flags))
         else:
             args.append("--disable-nls")
 
diff --git a/var/spack/repos/builtin/packages/systemtap/package.py b/var/spack/repos/builtin/packages/systemtap/package.py
index 99b44fb7e8..939f6cba0f 100644
--- a/var/spack/repos/builtin/packages/systemtap/package.py
+++ b/var/spack/repos/builtin/packages/systemtap/package.py
@@ -28,6 +28,7 @@ class Systemtap(AutotoolsPackage):
     depends_on("py-setuptools", type="build")
     depends_on("python", type=("build", "run"))
 
-    def configure_args(self):
-        args = ["LDFLAGS=-lintl"]
-        return args
+    def flag_handler(self, name, flags):
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
+            flags.append("-lintl")
+        return self.build_system_flags(name, flags)
diff --git a/var/spack/repos/builtin/packages/tar/package.py b/var/spack/repos/builtin/packages/tar/package.py
index ff7b9ef4a5..9e0c9b2e50 100644
--- a/var/spack/repos/builtin/packages/tar/package.py
+++ b/var/spack/repos/builtin/packages/tar/package.py
@@ -6,6 +6,7 @@
 import re
 
 from spack.package import *
+from spack.util.environment import is_system_path
 
 
 class Tar(AutotoolsPackage, GNUMirrorPackage):
@@ -62,23 +63,28 @@ class Tar(AutotoolsPackage, GNUMirrorPackage):
         return match.group(1) if match else None
 
     def configure_args(self):
+        spec = self.spec
         # Note: compression programs are passed by abs path,
         # so that tar can locate them when invoked without spack load.
         args = [
-            "--with-libiconv-prefix={0}".format(self.spec["iconv"].prefix),
-            "--with-xz={0}".format(self.spec["xz"].prefix.bin.xz),
-            "--with-lzma={0}".format(self.spec["xz"].prefix.bin.lzma),
-            "--with-bzip2={0}".format(self.spec["bzip2"].prefix.bin.bzip2),
+            "--with-xz={0}".format(spec["xz"].prefix.bin.xz),
+            "--with-lzma={0}".format(spec["xz"].prefix.bin.lzma),
+            "--with-bzip2={0}".format(spec["bzip2"].prefix.bin.bzip2),
         ]
 
-        if "^zstd" in self.spec:
-            args.append("--with-zstd={0}".format(self.spec["zstd"].prefix.bin.zstd))
+        if spec["iconv"].name == "libc":
+            args.append("--without-libiconv-prefix")
+        elif not is_system_path(spec["iconv"].prefix):
+            args.append("--with-libiconv-prefix={0}".format(spec["iconv"].prefix))
+
+        if "^zstd" in spec:
+            args.append("--with-zstd={0}".format(spec["zstd"].prefix.bin.zstd))
 
         # Choose gzip/pigz
-        zip = self.spec.variants["zip"].value
+        zip = spec.variants["zip"].value
         if zip == "gzip":
-            gzip_path = self.spec["gzip"].prefix.bin.gzip
+            gzip_path = spec["gzip"].prefix.bin.gzip
         elif zip == "pigz":
-            gzip_path = self.spec["pigz"].prefix.bin.pigz
+            gzip_path = spec["pigz"].prefix.bin.pigz
         args.append("--with-gzip={}".format(gzip_path))
         return args
diff --git a/var/spack/repos/builtin/packages/universal-ctags/package.py b/var/spack/repos/builtin/packages/universal-ctags/package.py
index a336b3c88b..6f7ca076b3 100644
--- a/var/spack/repos/builtin/packages/universal-ctags/package.py
+++ b/var/spack/repos/builtin/packages/universal-ctags/package.py
@@ -28,7 +28,7 @@ class UniversalCtags(AutotoolsPackage):
     depends_on("automake", type="build")
     depends_on("libtool", type="build")
     depends_on("m4", type="build")
-    depends_on("libiconv", type="link")
+    depends_on("iconv", type="link")
     depends_on("pkgconfig", type="build")
 
     def autoreconf(self, spec, prefix):
diff --git a/var/spack/repos/builtin/packages/xfd/package.py b/var/spack/repos/builtin/packages/xfd/package.py
index 8cd8288197..86bbc0ea2e 100644
--- a/var/spack/repos/builtin/packages/xfd/package.py
+++ b/var/spack/repos/builtin/packages/xfd/package.py
@@ -32,10 +32,9 @@ class Xfd(AutotoolsPackage, XorgPackage):
     # Xfd requires libintl (gettext), but does not test for it
     # correctly, so add it here.
     def flag_handler(self, name, flags):
-        if name == "ldlibs":
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
             flags.append("-lintl")
-
-        return (flags, None, None)
+        return self.inject_flags(name, flags)
 
     def configure_args(self):
         args = []
diff --git a/var/spack/repos/builtin/packages/xfsdump/package.py b/var/spack/repos/builtin/packages/xfsdump/package.py
index c078ef42db..0a9145bd02 100644
--- a/var/spack/repos/builtin/packages/xfsdump/package.py
+++ b/var/spack/repos/builtin/packages/xfsdump/package.py
@@ -25,8 +25,10 @@ class Xfsdump(MakefilePackage):
     depends_on("attr")
     depends_on("xfsprogs@:4.20.0")
 
-    def setup_build_environment(self, env):
-        env.append_flags("LDFLAGS", "-lintl")
+    def flag_handler(self, name, flags):
+        if name == "ldlibs" and "intl" in self.spec["gettext"].libs.names:
+            flags.append("-lintl")
+        return env_flags(name, flags)
 
     def build(self, spec, prefix):
         make(
diff --git a/var/spack/repos/builtin/packages/xfsprogs/package.py b/var/spack/repos/builtin/packages/xfsprogs/package.py
index 4813635df8..7fa6961591 100644
--- a/var/spack/repos/builtin/packages/xfsprogs/package.py
+++ b/var/spack/repos/builtin/packages/xfsprogs/package.py
@@ -25,21 +25,19 @@ class Xfsprogs(AutotoolsPackage):
     depends_on("util-linux")
 
     def flag_handler(self, name, flags):
-        iflags = []
         if name == "cflags":
             if self.spec.satisfies("@:5.4.0 %gcc@10:"):
-                iflags.append("-fcommon")
-        return (iflags, None, flags)
+                flags.append("-fcommon")
+        elif name == "ldlibs":
+            if "intl" in self.spec["gettext"].libs.names:
+                flags.append("-lintl")
+        return build_system_flags(name, flags)
 
     def setup_build_environment(self, env):
         env.append_path("C_INCLUDE_PATH", self.spec["util-linux"].prefix.include.blkid)
 
     def configure_args(self):
-        args = [
-            "LDFLAGS=-lintl",
-            "--with-systemd-unit-dir=" + self.spec["xfsprogs"].prefix.lib.systemd.system,
-        ]
-        return args
+        return ["--with-systemd-unit-dir=" + self.spec["xfsprogs"].prefix.lib.systemd.system]
 
     def install(self, spec, prefix):
         make("install")