--- a/calendar/lightning/lightning-packager.mk
+++ b/calendar/lightning/lightning-packager.mk
@@ -80,31 +80,28 @@ unpack: $(XPI_ZIP_IN)
 	$(NSINSTALL) -D $(XPI_STAGE_PATH)/$(XPI_NAME)
 	cd $(XPI_STAGE_PATH)/$(XPI_NAME) && $(UNZIP) $(XPI_ZIP_IN)
 	@echo done unpacking
 
 # Nothing to package for en-US, its just the usual english xpi
 langpack-en-US:
 	@echo "Skipping $@ as en-US is the default"
 
+merge-%: AB_CD=$*
 merge-%:
-ifdef LOCALE_MERGEDIR
-	$(RM) -rf $(LOCALE_MERGEDIR)/calendar
+	$(RM) -rf $(REAL_LOCALE_MERGEDIR)/calendar
 	$(MOZILLA_SRCDIR)/mach compare-locales \
-	    --merge-dir $(LOCALE_MERGEDIR) \
+	    --merge-dir $(REAL_LOCALE_MERGEDIR) \
 	    --l10n-ini $(topsrcdir)/calendar/locales/l10n.ini \
 	    $*
 
 	# This file requires a bugfix with string changes, see bug 1154448
 	[ -f $(L10NBASEDIR)/$*/calendar/chrome/calendar/calendar-extract.properties ] && \
-	  $(RM) $(LOCALE_MERGEDIR)/calendar/chrome/calendar/calendar-extract.properties \
+	  $(RM) $(REAL_LOCALE_MERGEDIR)/calendar/chrome/calendar/calendar-extract.properties \
 	  || true
-else
-	@echo "Not merging Lightning locales due to missing LOCALE_MERGEDIR"
-endif
 
 # Calling these targets with prerequisites causes the libs and subsequent
 # targets to be switched in order due to some make voodoo. Therefore we call
 # the targets explicitly, which seems to work better. Also, the
 # target-specific variable are not expanded for dependent targets.
 langpack-%: L10N_XPI_NAME=$(XPI_NAME)-$*
 langpack-%: L10N_XPI_PKGNAME=$(subst $(AB_CD),$*,$(XPI_PKGNAME))
 langpack-%: AB_CD=$*
@@ -131,17 +128,19 @@ repack-stage:
 
 
 # Actual locale packaging targets. If L10N_XPI_NAME is set, then use it.
 # Otherwise keep the original XPI_NAME
 # Overriding the final target is a bit of a hack for universal builds
 # so that we can ensure we get the right xpi that gets repacked.
 libs-%: FINAL_XPI_NAME=$(if $(L10N_XPI_NAME),$(L10N_XPI_NAME),$(XPI_NAME))
 libs-%: FINAL_XPI_PKGNAME=$(if $(L10N_XPI_PKGNAME),$(L10N_XPI_PKGNAME),$(XPI_PKGNAME))
+libs-%: AB_CD=$*
 libs-%:
+	@$(MAKE) merge-$*
 	$(MAKE) -C locales libs AB_CD=$* FINAL_TARGET=$(ABS_DIST)/xpi-stage/$(FINAL_XPI_NAME) \
 	  XPI_NAME=$(FINAL_XPI_NAME) XPI_PKGNAME=$(FINAL_XPI_PKGNAME) USE_EXTENSION_MANIFEST=1
 	$(MAKE) -C locales tools AB_CD=$* FINAL_TARGET=$(ABS_DIST)/xpi-stage/$(FINAL_XPI_NAME) \
 	  XPI_NAME=$(FINAL_XPI_NAME) XPI_PKGNAME=$(FINAL_XPI_PKGNAME) USE_EXTENSION_MANIFEST=1
 
 # The calling makefile might need to process some extra files. Provide an empty
 # rule to overwrite
 repack-process-extrafiles:
@@ -157,16 +156,18 @@ repack-process-extrafiles:
 	echo "BuildID=$(call print_ltnconfig,App,BuildID)" >> $(DIST)/bin/platform.ini
 
 recreate-platformini: $(DIST)/bin/platform.ini
 
 
 # Lightning uses Thunderbird's build machinery, so we need to hack the post
 # upload command to use Lightning's directories and version.
 upload: upload-$(AB_CD)
+
+upload-%: AB_CD=$*
 upload-%: LTN_UPLOAD_CMD := $(patsubst $(THUNDERBIRD_VERSION)%,$(LIGHTNING_VERSION),$(subst thunderbird,calendar/lightning,$(POST_UPLOAD_CMD)))
 upload-%: stage_upload
 	POST_UPLOAD_CMD="$(LTN_UPLOAD_CMD)" \
 	  $(PYTHON) $(MOZILLA_DIR)/build/upload.py --base-path $(DIST) \
 	  --properties-file $(DIST)/$(XPI_NAME)_build_properties.json \
 	  "$(DIST)/$(MOZ_PKG_PLATFORM)/$(XPI_PKGNAME).xpi"
 
 stage_upload:

--- a/mail/locales/Makefile.in
+++ b/mail/locales/Makefile.in
@@ -20,17 +20,17 @@ PWD := $(CURDIR)
 # pulls. You may override them if you provide your own files.
 ZIP_IN ?= $(ABS_DIST)/$(PACKAGE)
 WIN32_INSTALLER_IN ?= $(ABS_DIST)/$(PKG_INST_PATH)$(PKG_INST_BASENAME).exe
 RETRIEVE_WINDOWS_INSTALLER = 1
 
 MOZ_LANGPACK_EID=langpack-$(AB_CD)@thunderbird.mozilla.org
 # For Nightly, we know where to get the builds from to do local repacks
 ifdef NIGHTLY_BUILD
-EN_US_BINARY_URL=https://archive.mozilla.org/pub/thunderbird/nightly/latest-comm-central
+export EN_US_BINARY_URL ?= https://archive.mozilla.org/pub/thunderbird/nightly/latest-comm-central
 endif
 
 L10N_PREF_JS_EXPORTS = $(call MERGE_FILE,all-l10n.js)
 L10N_PREF_JS_EXPORTS_PATH = $(FINAL_TARGET)/$(PREF_DIR)
 L10N_PREF_JS_EXPORTS_FLAGS = $(PREF_PPFLAGS) --silence-missing-directive-warnings
 PP_TARGETS += L10N_PREF_JS_EXPORTS
 
 ifeq (cocoa,$(MOZ_WIDGET_TOOLKIT))
@@ -78,17 +78,24 @@ include $(topsrcdir)/mozilla/toolkit/loc
 
 $(list-json): $(call mkdir_deps,$(SEARCHPLUGINS_PATH)) $(if $(IS_LANGUAGE_REPACK),FORCE)
 	$(call py_action,generate_searchjson,$(srcdir)/search/list.json $(AB_CD) $(list-json))
 searchplugins:: $(list-json)
 
 $(DIST)/branding:
 	$(NSINSTALL) -D $@
 
+libs-%: AB_CD=$*
 libs-%:
+# merge if we're not en-US. Conditional function because
+# we need the current value of AB_CD.
+	$(if $(filter en-US,$(AB_CD)),, @$(MAKE) merge-$*)
+ifdef MOZ_CALENDAR
+	$(if $(filter en-US,$(AB_CD)),, @$(MAKE) -C ../../calendar/lightning merge-$*)
+endif
 	$(NSINSTALL) -D $(DIST)/install
 	@$(MAKE) -C $(DEPTH)/toolkit/locales libs-$*  XPI_ROOT_APPID='$(XPI_ROOT_APPID)'
 	@$(MAKE) -C $(DEPTH)/devtools/client/locales AB_CD=$* XPI_NAME=locale-$* XPI_ROOT_APPID='$(XPI_ROOT_APPID)'
 	@$(MAKE) -C ../../chat/locales AB_CD=$* XPI_NAME=locale-$*
 	@$(MAKE) -C ../../editor/ui/locales AB_CD=$* XPI_NAME=locale-$*
 	@$(MAKE) -C $(DEPTH)/extensions/spellcheck/locales AB_CD=$* XPI_NAME=locale-$*
 	@$(MAKE) -C $(DEPTH)/intl/locales AB_CD=$* XPI_NAME=locale-$*
 	@$(MAKE) -B searchplugins AB_CD=$* XPI_NAME=locale-$*
@@ -184,36 +191,36 @@ endif
 	chmod -vR 775 $(UPLOAD_DIR)
 
 # test target, depends on make package
 # try to repack x-test, with just toolkit/defines.inc being there
 l10n-check::
 	$(RM) -rf x-test
 	$(NSINSTALL) -D x-test/toolkit
 	echo '#define MOZ_LANG_TITLE Just testing' > x-test/toolkit/defines.inc
-	$(MAKE) installers-x-test L10NBASEDIR='$(PWD)' LOCALE_MERGEDIR='$(PWD)/mergedir'
+	$(MAKE) installers-x-test L10NBASEDIR='$(PWD)'
 
 ifdef MOZ_CALENDAR
 LIGHTNING_PATH=$(DEPTH)/calendar/lightning
 GDATA_PATH=$(DEPTH)/calendar/providers/gdata
 
 define run-calendar-rule
-$(MAKE) -C $(LIGHTNING_PATH) LOCALE_MERGEDIR=$(LOCALE_MERGEDIR) $(subst calendar-,,$@)
-$(MAKE) -C $(GDATA_PATH) LOCALE_MERGEDIR=$(LOCALE_MERGEDIR) $(subst calendar-,,$@)
+$(MAKE) -C $(LIGHTNING_PATH) $(subst calendar-,,$@) AB_CD=$(AB_CD)
+$(MAKE) -C $(GDATA_PATH) $(subst calendar-,,$@) AB_CD=$(AB_CD)
 endef
 
 # Add calendar targets for pattern rules. Unfortunately multiple pattern rules
 # on the left hand side do something different with make, therefore we need to
 # write a line for each target.
-calendar-merge-%:
-	$(run-calendar-rule)
 calendar-clobber-%:
 	$(run-calendar-rule)
+calendar-langpack-%: AB_CD=$*
 calendar-langpack-%:
 	$(run-calendar-rule)
+calendar-repackage-zip-%: AB_CD=$*
 calendar-repackage-zip-%:
 	$(run-calendar-rule)
 calendar-wget-en-US:
 	$(run-calendar-rule)
 calendar-unpack:
 	$(run-calendar-rule)
 calendar-upload:
 	$(MAKE) -C $(LIGHTNING_PATH) upload AB_CD=$(AB_CD)
@@ -226,17 +233,18 @@ MOZ_PKG_EXTRAL10N += distribution/extens
 endif
 
 # Hook calendar targets to the mail non-pattern rules
 wget-en-US: calendar-wget-en-US
 unpack: calendar-unpack
 upload: calendar-upload
 
 # Hook into the pattern rules, this will be used later on in the installers-% target.
-CALENDAR_INSTALLERS_TARGETS = calendar-merge-% calendar-clobber-% calendar-langpack-% calendar-repackage-zip-%
+CALENDAR_INSTALLERS_TARGETS = calendar-clobber-% calendar-langpack-% calendar-repackage-zip-%
 endif
 
 # This is a generic target that will make a langpack, repack ZIP (+tarball)
 # builds, and repack and installer if applicable. It is called from the
 # tinderbox scripts. Alter it with caution.
 INSTALLERS_TARGETS = clobber-% $(CALENDAR_INSTALLERS_TARGETS) langpack-% repackage-win32-installer-% repackage-zip-%
+installers-%: IS_LANGUAGE_REPACK=1
 installers-%: $(INSTALLERS_TARGETS)
 	@echo 'repackaging done'