This adds Hurd toolchain support to Clang's driver in addition to
handling
translating the triple from GCC toolchain-compatible form (x86_64-gnu)
to
the actual triple registered in LLVM (x86_64-pc-hurd-gnu).
- Unsupported Windows to drop backslashes code
- Upgrade to current gcc 10 version
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D101347
This is a follow-up of e92d2b80c6c9 ("[Driver] Detect libstdc++ include
paths for native gcc (-m32 and -m64) on Debian i386") for the Debian Hurd
case, which has the same multiarch name reduction from i686 to i386.
i386-linux-gnu is actually Linux-only, so this moves the code of that commit
to Linux.cpp, and adds the same to Hurd.cpp
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D101331
