patch 8.1.0987: unnecessary condition in #ifdef

Problem:    Unnecessary condition in #ifdef.
Solution:   Remove using CYGWIN32. (Ken Takata)
diff --git a/src/version.c b/src/version.c
index 3132a1d..e7d4923 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    987,
+/**/
     986,
 /**/
     985,