patch 8.0.1785: missing symbol in Win32 small build

Problem:    Missing symbol in Win32 small build.
Solution:   Define VTERM_ANSI_INDEX_NONE without the terminal feature. Also
            fix unused function with #ifdef.
diff --git a/src/version.c b/src/version.c
index 16d0eb0..01bd9a1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1785,
+/**/
     1784,
 /**/
     1783,