Bug 416450 - "Properly annotate recursive make invocation" (Mark MAKE_TIER_SUBMAKEFILES as a recursive make invocation) [p=jim@mozilla.com (Jim Blandy) r+a1.9=bsmedberg]

config/rules.mk

@@ -626,7 +626,7 @@ alldep::
 endif # TIERS
 endif # SUPPRESS_DEFAULT_RULES
 
-MAKE_TIER_SUBMAKEFILES = $(if $(tier_$*_dirs),$(MAKE) $(addsuffix /Makefile,$(tier_$*_dirs)))
+MAKE_TIER_SUBMAKEFILES = +$(if $(tier_$*_dirs),$(MAKE) $(addsuffix /Makefile,$(tier_$*_dirs)))
 
 export_tier_%: 
 	@echo "$@"