Automerge: [sanitizer_common] Older Haiku needs _GNU_SOURCE (#156291)

Co-authored-by: Jérôme Duval <[email protected]>
(cherry picked from commit 27c80fb)

Author: 2 people

compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

@@ -29,6 +29,7 @@
 #  include "sanitizer_solaris.h"
 
 #  if SANITIZER_HAIKU
+#    define _GNU_SOURCE
 #    define _DEFAULT_SOURCE
 #  endif