Make sure SOURCE_DATE_EPOCH actually contains something.
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
KBUILD_HAVE_NLS=no \
KBUILD_BUILD_USER="$(call qstrip,$(CONFIG_KERNEL_BUILD_USER))" \
KBUILD_BUILD_HOST="$(call qstrip,$(CONFIG_KERNEL_BUILD_DOMAIN))" \
- KBUILD_BUILD_TIMESTAMP="$(shell date -u --date="@$(SOURCE_DATE_EPOCH)")" \
+ $(if $(SOURCE_DATE_EPOCH),KBUILD_BUILD_TIMESTAMP="$(shell date -u --date="@$(SOURCE_DATE_EPOCH)")") \
KBUILD_BUILD_VERSION="0" \
CONFIG_SHELL="$(BASH)" \
$(if $(findstring c,$(OPENWRT_VERBOSE)),V=1,V='') \