https://bugs.gentoo.org/808480

From: Sergey Poznyakoff <gray@gnu.org>
Date: Wed, 7 Jul 2021 09:36:22 +0300
Subject: Fix https://puszcza.gnu.org.ua/bugs/?515

* src/gdbm.h.in: Include sys/types.h
--- a/src/gdbm.h.in
+++ b/src/gdbm.h.in
@@ -30,6 +30,7 @@
 # define _GDBM_H_
 
 # include <stdio.h>
+# include <sys/types.h>
 
 /* GDBM C++ support */
 # if defined(__cplusplus) || defined(c_plusplus)