kernel: Set SOURCE_DATE_EPOCH to kernel git timestamp if not set

If SOURCE_DATE_EPOCH is unset (in addition to the existing "0" behaviour)
parse out the top most commit timestamp from the kernel tree to use as the
timestamp.

(From OE-Core rev: 2f0dd67a5a8d4269f5155004d532d8fa972b3223)

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/meta/classes/kernel.bbclass b/meta/classes/kernel.bbclass
index 972ac52814..3213b932bf 100644
--- a/meta/classes/kernel.bbclass
+++ b/meta/classes/kernel.bbclass
@@ -288,7 +288,7 @@ kernel_do_compile() {
         if [ "${BUILD_REPRODUCIBLE_BINARIES}" = "1" ]; then
                 # kernel sources do not use do_unpack, so SOURCE_DATE_EPOCH may not
                 # be set....
-                if [ "$SOURCE_DATE_EPOCH" = "0" ]; then
+                if [ "${SOURCE_DATE_EPOCH}" = "" -o "${SOURCE_DATE_EPOCH}" = "0" ]; then
                         olddir=`pwd`
                         cd ${S}
                         SOURCE_DATE_EPOCH=`git log  -1 --pretty=%ct`