patch 8.2.4289: warnings reported by MSVC

Problem:    Warnings reported by MSVC.
Solution:   Rename variables and other fixes. (Ken Takata, closes #9689)
diff --git a/src/menu.c b/src/menu.c
index 880a93a..1c5cc4a 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -677,7 +677,7 @@
 		}
 	    }
 
-# if defined(FEAT_GUI_MSWIN) & defined(FEAT_TEAROFF)
+# if defined(FEAT_GUI_MSWIN) && defined(FEAT_TEAROFF)
 	    // When adding a new submenu, may add a tearoff item
 	    if (	addtearoff
 		    && *next_name