-# even for a crossbuild host build, we want to use the target's latest tzdata as pointed to by latest_tzdata.tar.gz
-ifeq "$(shell test -d $(SDKPATH)/usr/local/share/tz && echo YES )" "YES"
- export TZDATA:=$(SDKPATH)/usr/local/share/tz/$(shell readlink $(SDKPATH)/usr/local/share/tz/latest_tzdata.tar.gz)
+# even for a crossbuild host build, we want to use the target's latest tzdata as pointed to by latest_tzdata.tar.gz;
+# first try RC_EMBEDDEDPROJECT_DIR (<rdar://problem/28141177>), else SDKPATH.
+ifdef RC_EMBEDDEDPROJECT_DIR
+ ifeq "$(shell test -L $(RC_EMBEDDEDPROJECT_DIR)/TimeZoneData/usr/local/share/tz/latest_tzdata.tar.gz && echo YES )" "YES"
+ export TZDATA:=$(RC_EMBEDDEDPROJECT_DIR)/TimeZoneData/usr/local/share/tz/$(shell readlink $(RC_EMBEDDEDPROJECT_DIR)/TimeZoneData/usr/local/share/tz/latest_tzdata.tar.gz)
+ endif
+endif
+ifndef TZDATA
+ ifeq "$(shell test -L $(SDKPATH)/usr/local/share/tz/latest_tzdata.tar.gz && echo YES )" "YES"
+ export TZDATA:=$(SDKPATH)/usr/local/share/tz/$(shell readlink $(SDKPATH)/usr/local/share/tz/latest_tzdata.tar.gz)
+ endif