Windows rpath support (#31930)

Add a post-install step which runs (only) on Windows to modify an
install prefix, adding symlinks to all dependency libraries.

Windows does not have the same concept of RPATHs as Linux, but when
resolving symbols will check the local directory for dependency
libraries; by placing a symlink to each dependency library in the
directory with the library that needs it, the package can then
use all Spack-built dependencies.

Note:

* This collects dependency libraries based on Package.rpath, which
  includes only direct link dependencies
* There is no examination of libraries to check what dependencies
  they require, so all libraries of dependencies are symlinked
  into any directory of the package which contains libraries

1 files changed, 6 insertions, 6 deletions

diff --git a/var/spack/repos/builtin.mock/packages/attributes-foo/package.py b/var/spack/repos/builtin.mock/packages/attributes-foo/package.py
index f4bb9059a4..9010c52958 100644
--- a/var/spack/repos/builtin.mock/packages/attributes-foo/package.py
+++ b/var/spack/repos/builtin.mock/packages/attributes-foo/package.py
@@ -2,6 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import sys
 
 from spack.package import *
 
@@ -14,13 +15,12 @@ class AttributesFoo(BundlePackage):
     provides("baz")
 
     def install(self, spec, prefix):
-        if "platform=windows" in spec:
-            lib_suffix = ".lib"
-        elif "platform=darwin" in spec:
-            lib_suffix = ".dylib"
-        else:
-            lib_suffix = ".so"
 
+        lib_suffix = ".so"
+        if sys.platform == "win32":
+            lib_suffix = ".dll"
+        elif sys.platform == "darwin":
+            lib_suffix = ".dylib"
         mkdirp(prefix.include)
         touch(prefix.include.join("foo.h"))
         mkdirp(prefix.include.bar)