diff --git a/src/interfaces/libpq/fe-auth.c b/src/interfaces/libpq/fe-auth.c
index 3ed8c6c89ba..887ca5e9e1b 100644
--- a/src/interfaces/libpq/fe-auth.c
+++ b/src/interfaces/libpq/fe-auth.c
@@ -27,6 +27,7 @@
 #else
 #include <unistd.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <sys/param.h>			/* for MAXHOSTNAMELEN on most */
 #include <sys/socket.h>
 #ifdef HAVE_SYS_UCRED_H