patch 8.2.0837: compiler warning for value set but not used

Problem:    Compiler warning for value set but not used.
Solution:   Move variable inside #ifdef.
diff --git a/src/version.c b/src/version.c
index a88e478..a963bdc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    837,
+/**/
     836,
 /**/
     835,