diff --git a/src/sbbs3/mailsrvr.c b/src/sbbs3/mailsrvr.c
index 467a9f0c0f13e18780967d48a5313a2674b77a4a..e931eed80baff5907ccedb5c9a709394bd9d5081 100644
--- a/src/sbbs3/mailsrvr.c
+++ b/src/sbbs3/mailsrvr.c
@@ -29,6 +29,7 @@
 #include <errno.h>			/* errno */
 
 /* Synchronet-specific headers */
+#include "gen_defs.h"
 #undef SBBS	/* this shouldn't be defined unless building sbbs.dll/libsbbs.so */
 #include "sbbs.h"
 #include "mailsrvr.h"