Darwin systems need to be able to find CoreFoundation headers as well as
libc headers. Somehow, gcc doesn't accept any "framework" parameters
that would normally be used to include CoreFoundation in this
situation.
HACK: Instead, this adds a derivation that combines the two. The result
works but probably not a good long term solution.
ALTERNATIVES: Maybe sending patches in to GCC to allow
"native-system-framework" configure flag to get this found.
gcc needs to be able find system headers. Without this, gcc fails to build because
/usr/include is not available.
Note: stdenv.libc should be available for all stdenv's, I think.
This should get gcc48, gcc5, and gcc6 working again.
Also: use makeLibraryPath, and makeSearchPathOutput for LIBRARY_PATH and
CPATH. This is a refactor but it also fixes an issue with zlib.
- disable bootstrap builds on Darwin
- remove xcrun calls
- check if patchelf is available before using
- apply darwin patch for gcc4.9
- fixes#16047
- fixes#14812
