PR sanitizer/59136
libsanitizer/
	* sanitizer_common/Makefile.am (AM_CXXFLAGS): If
	LIBBACKTRACE_SUPPORTED add -DSANITIZER_LIBBACKTRACE
	and -I/-include flags.
	* lsan/Makefile.am (liblsan_la_LIBADD): Add
	libsanitizer_libbacktrace.la if LIBBACKTRACE_SUPPORTED.
	* tsan/Makefile.am (libtsan_la_LIBADD): Likewise.
	* ubsan/Makefile.am (libubsan_la_LIBADD): Likewise.
	* asan/Makefile.am (libasan_la_LIBADD): Likewise.
	* Makefile.am (SUBDIRS): If LIBBACKTRACE_SUPPORTED add
	libbacktrace.
	* README.gcc: Document that also lsan and ubsan are
	maintained in compiler-rt upstream.
	* libbacktrace/Makefile.am: New file.
	* libbacktrace/backtrace-rename.h: New file.
	* libbacktrace/backtrace-supported.h.in: New file.
	* libbacktrace/bridge.cc: New file.
	* configure.ac: Add tests needed for libbacktrace build
	within libsanitizer.
	* sanitizer_common/Makefile.in: Regenerated.
	* lsan/Makefile.in: Regenerated.
	* tsan/Makefile.in: Regenerated.
	* ubsan/Makefile.in: Regenerated.
	* libbacktrace/Makefile.in: Generated.
	* config.h.in: Regenerated.
	* configure: Regenerated.
	* Makefile.in: Regenerated.
	* interception/Makefile.in: Regenerated.
	* asan/Makefile.in: Regenerated.
	* aclocal.m4: Regenerated.
testsuite/
	* c-c++-common/asan/strip-path-prefix-1.c: Allow also the
	filename:line instead of (modulename+offset) form with stripped
	initial / from the filename.

From-SVN: r206475