Restore @ accidentally deleted by my checkin for bug 285627 r=bsmedberg

config/rules.mk

@@ -1764,7 +1764,7 @@ ifdef PERL
 # because it handles the case when header files are removed from the build.
 # 'make' would complain that there is no way to build missing headers.
 $(MDDEPDIR)/.all.pp: FORCE
-	$(PERL) $(BUILD_TOOLS)/mddepend.pl $@ $(MDDEPEND_FILES)
+	@$(PERL) $(BUILD_TOOLS)/mddepend.pl $@ $(MDDEPEND_FILES)
 -include $(MDDEPDIR)/.all.pp
 else
 include $(MDDEPEND_FILES)