patch 8.1.0730: compiler warning for get_buf_arg() unused

Problem:    Compiler warning for get_buf_arg() unused.
Solution:   Add #ifdef. (John Marriott)
diff --git a/src/version.c b/src/version.c
index 118a867..7aeaa48 100644
--- a/src/version.c
+++ b/src/version.c
@@ -796,6 +796,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    730,
+/**/
     729,
 /**/
     728,