patch 9.0.1817: configure: using obsolete AC_HEADER_STDC

Problem:  configure: using obsolete AC_HEADER_STDC
Solution: Remove it and re-create configure

closes: #12949

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Illia Bobyr <illia.bobyr@gmail.com>
diff --git a/src/version.c b/src/version.c
index 8a755f0..74b8000 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1817,
+/**/
     1816,
 /**/
     1815,