clang-cc: Remove some more llvm::cl::init arguments, by only setting values when
the argument is given.

Also, tweak Opt.Sysroot defaulting.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89318 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed