Allow parallel make (-j) to work properly.

1.4 changes are quite different from the others.

(issue #16489)
Reported by: Chainsaw
Tested by: qwell


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@241228 65c4cc65-6c06-0410-ace0-fbb531ad65f3

Makefile

@@ -336,8 +336,8 @@ $(MOD_SUBDIRS_EMBED_LIBS):
 	+@echo "EMBED_LIBS+="`$(SUBMAKE) -C $(@:-embed-libs=) SUBDIR=$(@:-embed-libs=) __embed_libs` >> makeopts.embed_rules
 
 $(MOD_SUBDIRS_MENUSELECT_TREE):
-	@$(SUBMAKE) -C $(@:-menuselect-tree=) SUBDIR=$(@:-menuselect-tree=) moduleinfo
-	@$(SUBMAKE) -C $(@:-menuselect-tree=) SUBDIR=$(@:-menuselect-tree=) makeopts
+	+@$(SUBMAKE) -C $(@:-menuselect-tree=) SUBDIR=$(@:-menuselect-tree=) moduleinfo
+	+@$(SUBMAKE) -C $(@:-menuselect-tree=) SUBDIR=$(@:-menuselect-tree=) makeopts
 
 makeopts.embed_rules: menuselect.makeopts
 	@echo "Generating embedded module rules ..."