patch 8.1.0486: can't build in MS-Windows

Problem:    Can't build in MS-Windows.
Solution:   Put mch_access() call inside #ifdef
diff --git a/src/version.c b/src/version.c
index 4ed8adc..726f5ee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -793,6 +793,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    486,
+/**/
     485,
 /**/
     484,