Fix libcxx build with glibc 2.26+ by removing xlocale.h include.
Fix libcxx build with glibc 2.26+ by removing xlocale.h include.

Patch by Khem Raj. Reviewed as D35697. Also see PR33729.



git-svn-id: 756ef344af921d95d562d9e9f9389127a89a6314@309920 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx,llvm-mirror/libcxx