diff --git a/src/include/c.h b/src/include/c.h
index cb8a38669be..8e887bec0b2 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -60,6 +60,7 @@
 
 /* System header files that should be available everywhere in Postgres */
 #include <inttypes.h>
+#include <stdalign.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>