patch 8.1.0102: cannot build without syntax highlighting

Problem:    Cannot build without syntax highlighting.
Solution:   Add #ifdef around using reg_do_extmatch.
diff --git a/src/version.c b/src/version.c
index a2da37e..a38cdda 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    102,
+/**/
     101,
 /**/
     100,