patch 8.1.1661: cannot build with +textprop but without +balloon_eval

Problem:    Cannot build with +textprop but without +balloon_eval.
Solution:   Adjust #ifdefs. (closes #4645)
diff --git a/src/version.c b/src/version.c
index 6af9aba..9e8fcba 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1661,
+/**/
     1660,
 /**/
     1659,