clean up FORTIFY_SOURCE handling.

Avoid duplicating huge chunks of code.

Change-Id: Id6145cdfce781c5ffba2abaaa79681d25a7ab28f
diff --git a/libc/private/logd.h b/libc/private/logd.h
index 26878ba..a2828ec 100644
--- a/libc/private/logd.h
+++ b/libc/private/logd.h
@@ -71,6 +71,8 @@
 void __libc_android_log_event_int(int32_t tag, int value);
 void __libc_android_log_event_uid(int32_t tag);
 
+__noreturn extern void __fortify_chk_fail(const char *, uint32_t);
+
 #ifdef __cplusplus
 };
 #endif