[Bug sanitizer/61021] [4.9 regression] libsanitizer fails to build with old glibc

[sandra at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61021

--- Comment #3 from Sandra Loosemore <sandra at codesourcery dot com> ---
Patch sent to llvm-commits.

For now I can unblock my work by applying the patch locally, but this isn't
something we'd want to carry around permanently and have to apply to future
versions of GCC, especially if it is the wrong way to solve the problem.