clear record of installed chrome at beginning of install

config/Makefile.in

@@ -55,6 +55,7 @@ ifdef NSBUILDROOT
 override NSBUILDROOT :=
 endif
 
+include $(topsrcdir)/config/config.mk
 include $(topsrcdir)/config/rules.mk
 
 ifeq ($(OS_ARCH), Linux)
@@ -87,6 +88,10 @@ $(DEPTH)/build/build_number: FORCE
 $(DEPTH)/modules/libpref/src/init/all.js: FORCE
 	$(PERL) $(srcdir)/set-timebomb.pl 0 30
 
+# clear record of installed chrome on complete rebuild
+install::
+	$(RM) $(DIST)/bin/chrome/installed-chrome.txt
+
 FORCE:
 
 ifdef MKDEPEND_DIR