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diff --git a/var/spack/repos/builtin/packages/apple-libunwind/package.py b/var/spack/repos/builtin/packages/apple-libunwind/package.py
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+# Copyright 2013-2018 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class AppleLibunwind(Package):
+    """Placeholder package for Apple's analogue to non-GNU libunwind"""
+
+    homepage = "https://opensource.apple.com/source/libunwind/libunwind-35.3/"
+
+    provides('unwind')
+
+    # The 'conflicts' directive only accepts valid spack specs;
+    # platforms cannot be negated -- 'platform!=darwin' is not a valid
+    # spec -- so expressing a conflict for any platform that isn't
+    # Darwin must be expressed by listing a conflict with every
+    # platform that isn't Darwin/macOS
+    conflicts('platform=linux')
+    conflicts('platform=bgq')
+    conflicts('platform=cray')
+
+    # Override the fetcher method to throw a useful error message;
+    # avoids GitHub issue (#7061) in which the opengl placeholder
+    # package threw a generic, uninformative error during the `fetch`
+    # step,
+    @property
+    def fetcher(self):
+        msg = """This package is intended to be a placeholder for Apple's
+        system-provided, non-GNU-compatible libunwind library.
+
+        Add to your packages.yaml:
+
+        packages:
+          apple-libunwind:
+            paths:
+              apple-libunwind@35.3: /usr
+            buildable: False
+
+        """
+        raise InstallError(msg)
+
+    def install(self, spec, prefix):
+        pass
+
+    @property
+    def libs(self):
+        """Export the Apple libunwind library. The Apple libunwind library
+        cannot be linked to directly using an absolute path; doing so
+        will cause the linker to throw an error 'cannot link directly
+        with /usr/lib/system/libunwind.dylib' and the linker will
+        suggest linking with System.framework instead. Linking to this
+        framework is equivalent to linking with libSystem.dylib, which
+        can be confirmed on a macOS system by executing at a terminal
+        the command `ls -l
+        /System/Library/Frameworks/System.Framework` -- the file
+        "System" is a symlink to `/usr/lib/libSystem.B.dylib`, and
+        `/usr/lib/libSystem.dylib` also symlinks to this file.
+
+        Running `otool -L /usr/lib/libSystem.dylib` confirms that
+        it will link dynamically to `/usr/lib/system/libunwind.dylib`.
+
+        """
+        libs = find_libraries('libSystem',
+                              self.prefix.lib,
+                              shared=True, recursive=False)
+        if libs:
+            return libs
+        return None
+
+    @property
+    def headers(self):
+        """ Export the Apple libunwind header
+        """
+        hdrs = HeaderList(find(self.prefix.include, 'libunwind.h',
+                               recursive=False))
+        return hdrs or None