patch 8.0.0506: can't build with ANSI C

Problem:    Can't build with ANSI C.
Solution:   Move declarations to start of block.
diff --git a/src/version.c b/src/version.c
index 9717094..e19da86 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    506,
+/**/
     505,
 /**/
     504,