[cxxmodules] Re-attach the standard modulemaps on osx.
[cxxmodules] Re-attach the standard modulemaps on osx.

This should fix the regressed runtime_cxxmodules on osx.

Patch by Alexander Penev!

olifre/root,olifre/root,olifre/root,karies/root,root-mirror/root,karies/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,karies/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,karies/root,olifre/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,olifre/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,karies/root