diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index f0091b09cbe..2dd8f6b9a38 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -54,9 +54,6 @@
 /* Define to 1 if you have the `append_history' function. */
 #undef HAVE_APPEND_HISTORY
 
-/* Define to 1 if you have the <atomic.h> header file. */
-#undef HAVE_ATOMIC_H
-
 /* Define to 1 if you have the `backtrace_symbols' function. */
 #undef HAVE_BACKTRACE_SYMBOLS
 
@@ -281,9 +278,6 @@
 /* Define to 1 if you have the `localeconv_l' function. */
 #undef HAVE_LOCALECONV_L
 
-/* Define to 1 if you have the <mbarrier.h> header file. */
-#undef HAVE_MBARRIER_H
-
 /* Define to 1 if you have the `mbstowcs_l' function. */
 #undef HAVE_MBSTOWCS_L