rootfs.mk: ensure all timestamp are set to SOURCE_DATE_EPOCH

Some tools doesn't support SOURCE_DATE_EPOCH (e.g. initramfs images).
Ensure all files of a root filesystem are set to SOURCE_DATE_EPOCH.
Make initramfs builds reproducible (for ramips).

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>

diff --git a/include/rootfs.mk b/include/rootfs.mk
index f2d2494ae26445d1a8f79eefecd2887a868a88ab..b6775c7e15fb00e935737fd0b801ca7bef6e2a0d 100644 (file)
--- a/include/rootfs.mk
+++ b/include/rootfs.mk
@@ -99,4 +99,5 @@ define prepare_rootfs
        rm -rf $(1)/boot
        $(call clean_ipkg,$(1))
        $(call mklibs,$(1))
+       $(if $(SOURCE_DATE_EPOCH),find $(1)/ -mindepth 1 -execdir touch -hcd "@$(SOURCE_DATE_EPOCH)" "{}" +)
 endef