patch 8.1.1230: a lot of code is shared between vim.exe and gvim.exe

Problem:    A lot of code is shared between vim.exe and gvim.exe.
Solution:   Optionally put the shared code in vim.dll. (Ken Takata,
            closes #4287)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 509a31f..e65ab94 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -4201,11 +4201,13 @@
 {
 #ifdef FEAT_GUI
     if (gui.in_use)
+    {
 	gui_mch_set_foreground();
-#else
-# ifdef MSWIN
+	return;
+    }
+#endif
+#if defined(MSWIN) && (!defined(FEAT_GUI) || defined(VIMDLL))
     win32_set_foreground();
-# endif
 #endif
 }