[openwrt/openwrt] imagebuilder: export SOURCE_DATE_EPOCH to environment

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/50cb1cb2efa9cac3df1e6b73f5501b01c270e860

commit 50cb1cb2efa9cac3df1e6b73f5501b01c270e860
Author: Daniel Golle <daniel at makrotopia.org>
AuthorDate: Sun Apr 10 00:55:21 2022 +0100

    imagebuilder: export SOURCE_DATE_EPOCH to environment
    
    Export SOURCE_DATE_EPOCH to environment so filesystem and image
    creation tools will make use of it.
    Fixes reproducibility of images generated with the ImageBuilder.
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
    (cherry picked from commit 5cf5dce05ae829ec848ad63a6da300c4fddcd510)
---
 target/imagebuilder/files/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/imagebuilder/files/Makefile b/target/imagebuilder/files/Makefile
index 871a40b3a1..3329fe70aa 100644
--- a/target/imagebuilder/files/Makefile
+++ b/target/imagebuilder/files/Makefile
@@ -27,6 +27,7 @@ include $(INCLUDE_DIR)/rootfs.mk
 
 include $(INCLUDE_DIR)/version.mk
 export REVISION
+export SOURCE_DATE_EPOCH
 
 define Helptext
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