CMakePackage: allow custom CMAKE_PREFIX_PATH entries (#32547)

* define `cmake_prefix_paths` property for packages

add to CMake arguments via CMakePackage

Co-authored-by: Robert Underwood <runderwood@anl.gov>

lib/spack/spack/build_environment.py

@@ -1030,8 +1030,11 @@ def get_cmake_prefix_path(pkg):
                 spack_built.insert(0, dspec)
 
     ordered_build_link_deps = spack_built + externals
-    build_link_prefixes = filter_system_paths(x.prefix for x in ordered_build_link_deps)
-    return build_link_prefixes
+    cmake_prefix_path_entries = []
+    for spec in ordered_build_link_deps:
+        cmake_prefix_path_entries.extend(spec.package.cmake_prefix_paths)
+
+    return filter_system_paths(cmake_prefix_path_entries)
 
 
 def _setup_pkg_and_run(

lib/spack/spack/package_base.py

@@ -1740,6 +1740,10 @@ def content_hash(self, content=None):
 
         return b32_hash
 
+    @property
+    def cmake_prefix_paths(self):
+        return [self.prefix]
+
     def _has_make_target(self, target):
         """Checks to see if 'target' is a valid target in a Makefile.
 

lib/spack/spack/test/packages.py

@@ -133,6 +133,14 @@ def test_url_for_version_with_no_urls(mock_packages, config):
         pkg_cls(spec).url_for_version("1.1")
 
 
+def test_custom_cmake_prefix_path(mock_packages, config):
+    spec = Spec("depends-on-define-cmake-prefix-paths").concretized()
+
+    assert spack.build_environment.get_cmake_prefix_path(spec.package) == [
+        spec["define-cmake-prefix-paths"].prefix.test
+    ]
+
+
 def test_url_for_version_with_only_overrides(mock_packages, config):
     s = Spec("url-only-override").concretized()