diff --git a/src/include/c.h b/src/include/c.h
index b038aa4e4..57dd2a9aa 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -112,24 +112,6 @@
 #define dngettext(d, s, p, n) ((n) == 1 ? (s) : (p))
 #endif
 
-/* only GCC supports the unused attribute */
-#ifdef __GNUC__
-#define pg_attribute_unused() __attribute__((unused))
-#else
-#define pg_attribute_unused()
-#endif
-
-/*
- * Append PG_USED_FOR_ASSERTS_ONLY to definitions of variables that are only
- * used in assert-enabled builds, to avoid compiler warnings about unused
- * variables in assert-disabled builds.
- */
-#ifdef USE_ASSERT_CHECKING
-#define PG_USED_FOR_ASSERTS_ONLY
-#else
-#define PG_USED_FOR_ASSERTS_ONLY pg_attribute_unused()
-#endif
-
 /*
  *	Use this to mark string constants as needing translation at some later
  *	time, rather than immediately.	This is useful for cases where you need