patch 8.1.0941: macros for MS-Windows are inconsistent

Problem:    Macros for MS-Windows are inconsistent, using "32", "3264 and
            others.
Solution:   Use MSWIN for all MS-Windows builds.  Use FEAT_GUI_MSWIN for the
            GUI build. (Hirohito Higashi, closes #3932)
diff --git a/src/vim.rc b/src/vim.rc
index 492c74b..c3d3f5f 100644
--- a/src/vim.rc
+++ b/src/vim.rc
@@ -23,7 +23,7 @@
 //
 IDR_VIM		ICON "vim.ico"
 
-#ifdef FEAT_GUI_W32
+#ifdef FEAT_GUI
 IDR_VIM_ERROR	ICON "vim_error.ico"
 IDR_VIM_ALERT	ICON "vim_alert.ico"
 IDR_VIM_INFO	ICON "vim_info.ico"
@@ -46,7 +46,7 @@
 #endif
 
 CREATEPROCESS_MANIFEST_RESOURCE_ID RT_MANIFEST "gvim.exe.mnf"
-#endif // FEAT_GUI_W32
+#endif // FEAT_GUI
 
 //
 // Type Library