diff --git a/libraries/liblutil/debug.c b/libraries/liblutil/debug.c
index a46cba150c..ddb30ed96b 100644
--- a/libraries/liblutil/debug.c
+++ b/libraries/liblutil/debug.c
@@ -57,7 +57,11 @@ void (lutil_debug)( int level, int debug, const char *fmt, ... )
 
 	va_start( vl, fmt );
 
+#ifdef HAVE_VSNPRINTF
 	vsnprintf( buffer, sizeof(buffer), fmt, vl );
+#else
+	vsprintf( buffer, fmt, vl );
+#endif
 	buffer[sizeof(buffer)-1] = '\0';
 
 	if( log_file != NULL ) {