Summary: When using the C preprocessor with assembly files, either with a
capital `S` file extension, or with `-xassembler-with-cpp`, the Unicode escape
sequence `\u` is ignored. The `\u` pattern can be used for expanding a macro
argument that starts with `u`.
Author: Salman Arif <salman.arif@arm.com>
Reviewers: rengolin, olista01
Reviewed By: olista01
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D31765
llvm-svn: 299754