patch 8.2.0673: cannot build Haiku in shadow directory

Problem:    Cannot build Haiku in shadow directory.
Solution:   Add symlink. (Ozaki Kiichi, closes #6023)
diff --git a/src/Makefile b/src/Makefile
index 12ec23c..8a12cb8 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2918,7 +2918,7 @@
 #  % make
 SHADOWDIR = shadow
 
-LINKEDFILES = ../*.[chm] ../*.in ../*.sh ../*.xs ../*.xbm ../gui_gtk_res.xml ../toolcheck ../proto ../libvterm ../vimtutor ../gvimtutor ../install-sh ../Make_all.mak
+LINKEDFILES = ../*.[chm] ../*.cc ../*.in ../*.sh ../*.xs ../*.xbm ../gui_gtk_res.xml ../toolcheck ../proto ../libvterm ../vimtutor ../gvimtutor ../install-sh ../Make_all.mak
 
 shadow:	runtime pixmaps
 	$(MKDIR_P) $(SHADOWDIR)