Filter system paths from CMAKE_PREFIX_PATH (#5385)

lib/spack/spack/build_systems/cmake.py

@@ -29,6 +29,7 @@
 
 import spack.build_environment
 from llnl.util.filesystem import working_dir, join_path
+from spack.util.environment import filter_system_paths
 from spack.directives import depends_on, variant
 from spack.package import PackageBase, InstallError, run_after
 
@@ -149,6 +150,7 @@ def _std_args(pkg):
         # to find immediate link dependencies in right places:
         deps = [d.prefix for d in
                 pkg.spec.dependencies(deptype=('build', 'link'))]
+        deps = filter_system_paths(deps)
         args.append('-DCMAKE_PREFIX_PATH:STRING={0}'.format(';'.join(deps)))
         return args