patch 8.2.2691: autoconf may mess up compiler flags

Problem:    Autoconf may mess up compiler flags.
Solution:   Handle removing FORTIFY_SOURCE a bit better. (Vladimir Lomov,
            closes #8049)
diff --git a/src/version.c b/src/version.c
index 7e446dc..72b7987 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2691,
+/**/
     2690,
 /**/
     2689,