Implement a -gcc-toolchain command line option that does the same as
configure's --with-gcc-toolchain. The configure option is now just a default
value for the command line one.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150898 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed