patch 8.1.0153: build with SHADOWDIR fails

Problem:    Build with SHADOWDIR fails. (Elimar Riesebieter)
Solution:   Create a link for Make_all.mak. (Tony Mechelynck)
diff --git a/src/Makefile b/src/Makefile
index 2c4421e..8459546 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2681,7 +2681,7 @@
 
 shadow:	runtime pixmaps
 	$(MKDIR_P) $(SHADOWDIR)
-	cd $(SHADOWDIR); ln -s ../*.[chm] ../*.in ../*.sh ../*.xs ../*.xbm ../gui_gtk_res.xml ../toolcheck ../proto ../libvterm ../vimtutor ../gvimtutor ../install-sh .
+	cd $(SHADOWDIR); ln -s ../*.[chm] ../*.in ../*.sh ../*.xs ../*.xbm ../gui_gtk_res.xml ../toolcheck ../proto ../libvterm ../vimtutor ../gvimtutor ../install-sh ../Make_all.mak .
 	mkdir $(SHADOWDIR)/auto
 	cd $(SHADOWDIR)/auto; ln -s ../../auto/configure .
 	$(MKDIR_P) $(SHADOWDIR)/po