patch 8.0.1581: cannot build Win32 GUI without +eval

Problem:    Cannot build Win32 GUI without +eval.
Solution:   Define HAVE_INPUT_METHOD without +eval. (Ken Takata)
diff --git a/src/version.c b/src/version.c
index 9985b4f..002aded 100644
--- a/src/version.c
+++ b/src/version.c
@@ -767,6 +767,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1581,
+/**/
     1580,
 /**/
     1579,