patch 8.2.0320: no Haiku support

Problem:    No Haiku support.
Solution:   Add support for Haiku. (Emir Sari, closes #5605)
diff --git a/src/menu.c b/src/menu.c
index d82f04d..c57a6c1 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -2525,7 +2525,7 @@
 }
 
 #if defined(FEAT_GUI_MSWIN) || defined(FEAT_GUI_GTK) \
-	|| defined(FEAT_TERM_POPUP_MENU) \
+	|| defined(FEAT_TERM_POPUP_MENU) || defined(FEAT_GUI_HAIKU) \
 	|| defined(FEAT_BEVAL_TIP) || defined(PROTO)
 /*
  * Given a menu descriptor, e.g. "File.New", find it in the menu hierarchy.