patch 8.0.1730: no configure check for the used C99 features

Problem:    No configure check for the used C99 features.
Solution:   Add a compilation check.  Tentatively document C99 features.
diff --git a/src/version.c b/src/version.c
index aa1e93f..8d5c73a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -763,6 +763,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1730,
+/**/
     1729,
 /**/
     1728,