* sanitizer_common/sanitizer_symbolizer_libbacktrace.cc,
	sanitizer_common/sanitizer_symbolizer_libbacktrace.h,
	sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc: Cherry pick
	upstream r224308.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@218778 138bc75d-0d04-0410-961f-82ee72b054a4