base: include config.h

Solaris requires __EXTENSIONS__ to be defined before including string.h so that
the strnlen() prototype is visible

lib/base/db.c

@@ -47,6 +47,8 @@
  * memory-based rollback log is used).
  */
 
+#include "config.h"
+
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>