reproducible: enable fakedate

Enable fakedate for whole build process.

This work was sponsored by `BA Robotic Systems'.

Signed-off-by: Jérôme Pouiller <jezz@sysmic.org>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Makefile

@@ -254,6 +254,7 @@ export LC_ALL = C
 export GZIP = -n
 BR2_VERSION_GIT_EPOCH = $(shell GIT_DIR=$(TOPDIR)/.git $(GIT) log -1 --format=%at)
 export SOURCE_DATE_EPOCH = $(if $(wildcard $(TOPDIR)/.git),$(BR2_VERSION_GIT_EPOCH),$(BR2_VERSION_EPOCH))
+DEPENDENCIES_HOST_PREREQ += host-fakedate
 endif
 
 # To put more focus on warnings, be less verbose as default