patch 8.0.0691: compiler warning without the linebreak feature

Problem:    Compiler warning without the linebreak feature.
Solution:   Add #ifdef. (John Marriott)
diff --git a/src/version.c b/src/version.c
index 27f0436..4e7558a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    691,
+/**/
     690,
 /**/
     689,