[sanitizer_common] Updated build fix for newer NetBSD (#134742)

Co-authored-by: Thomas Klausner <wiz@gatalith.at>

Author: brad0

compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

@@ -34,11 +34,12 @@
 
 #  if SANITIZER_NETBSD
 #    // for __lwp_gettcb_fast() / __lwp_getprivate_fast()
+#    define _RTLD_SOURCE
+#    include <machine/mcontext.h>
+#    undef _RTLD_SOURCE
 #    include <sys/param.h>
-#    if defined(__NetBSD_Version__) && (__NetBSD_Version__ >= 1099001200)
+#    if __NetBSD_Version__ >= 1099001200
 #      include <machine/lwp_private.h>
-#    else
-#      define _RTLD_SOURCE
 #    endif
 #  endif