The plan is to use it for clang and lld.
Major behavior changes:
- We can now parse UTF-16 files that have a byte order mark.
- PR16209: Don't drop backslashes on the floor if they don't escape
anything.
The actual parsing loop was based on code from Clang's driver.cpp,
although it's been rewritten to track its state with control flow rather
than state variables.
Reviewers: hans
Differential Revision: http://llvm-reviews.chandlerc.com/D1170
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186587 91177308-0d34-0410-b5e6-96231b3b80d8
