diff --git a/src/sbbs3/userdat.c b/src/sbbs3/userdat.c
index 82e5df64dd57d37f2af959242e39bb4b8bded386..4a8e8d2ae0b5f8400751441b12dd8f6a53ffb85d 100644
--- a/src/sbbs3/userdat.c
+++ b/src/sbbs3/userdat.c
@@ -37,6 +37,9 @@
 
 #include "sbbs.h"
 #include "cmdshell.h"
+#ifndef USHRT_MAX
+	#define USHRT_MAX ((1<<sizeof(unsigned short))-1)
+#endif
 
 /* convenient space-saving global variables */
 char* crlf="\r\n";