patch 8.2.4405: compiler warning for unused variable without +folding

Problem:    Compiler warning for unused variable without the +folding feature.
            (Tony Mechelynck)
Solution:   Add #ifdef.
diff --git a/src/version.c b/src/version.c
index 3c4e6b0..3b3beba 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4405,
+/**/
     4404,
 /**/
     4403,