Fix for selfbuild to use both CC and CXX, but not only CC.
Merge pull request #917 from dbabokin/selfbuild

Fix for selfbuild to use both CC and CXX, but not only CC.
Removing -debug-ir functionality for 3.6, as it was removed from LLVM.
Merge pull request #918 from dbabokin/trunk

Removing -debug-ir functionality for 3.6, as it was removed from LLVM.