Summary:
The main section of this patch teaches CMake a new option `LIBCXXABI_LIBCXX_PATH` that specifies the path to the libcxx source root. This information is passed to lit so that it can better find libc++'s python module. `LIBCXXABI_LIBCXX_PATH` is also used to help find the libc++ headers.
The rest of this patch is misc cleanup, mostly to make pep8 and pylint happy.
I've also copied libc++'s .gitignore into libc++abi.
Reviewers: jroelofs, danalbert
Reviewed By: danalbert
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7130
llvm-svn: 226855