patch 7.4.1637
Problem:    Can't build with older MinGW compiler.
Solution:   Change option from c++11 to gnu++11. (Ken Takata)
diff --git a/src/version.c b/src/version.c
index d28ad94..c9f1926 100644
--- a/src/version.c
+++ b/src/version.c
@@ -749,6 +749,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1637,
+/**/
     1636,
 /**/
     1635,