--- a/Makefile.in
+++ b/Makefile.in
@@ -96,17 +96,22 @@ ifeq ($(OS_ARCH),WINNT)
   MAKE_SYM_STORE_PATH=..
 endif
 
 buildsymbols ::
 	$(MAKE) -C mozilla MAKE_SYM_STORE_PATH=$(MAKE_SYM_STORE_PATH) SYM_STORE_SOURCE_DIRS="$(topsrcdir)/mozilla/extensions/inspector $(topsrcdir)/mozilla $(topsrcdir)" $@
 
 include $(topsrcdir)/config/rules.mk
 
+# m-1.9.2 doesn't have this at all, but non-branched c-c does.
+ifdef MOZILLA_1_9_2_BRANCH
 MOZ_SOURCE_STAMP = $(shell hg -R $(srcdir) parent --template="{node|short}\n" 2>/dev/null)
+else
+# defined in package-name.mk
+endif
 export MOZ_SOURCE_STAMP
 
 DIST_GARBAGE = config.cache config.log config.status config-defs.h \
    dependencies.beos \
    unallmakefiles mozilla-config.h \
    $(topsrcdir)/.mozconfig.mk $(topsrcdir)/.mozconfig.out
 
 distclean::