--- a/mysql_fdw.h
+++ b/mysql_fdw.h
@@ -36,7 +36,9 @@
 
 #define MYSQL_PREFETCH_ROWS	100
 #define MYSQL_BLKSIZ		(1024 * 4)
-#define MYSQL_PORT			3306
+#ifndef MYSQL_PORT
+#  define MYSQL_PORT			3306
+#endif
 #define MAXDATALEN			1024 * 64
 
 #define WAIT_TIMEOUT		0