patch 8.0.1808: can't build without TGETENT

Problem:    Can't build without TGETENT.
Solution:   Add #ifdef
diff --git a/src/version.c b/src/version.c
index 147f4ed..db47bea 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1808,
+/**/
     1807,
 /**/
     1806,