image-prelink.bbclass: support binary reproducibility
Conditionally support binary reproducibility in built images.
If BUILD_REPRODUCIBLE_BINARIES = 1 then:
1. Do not randomize library addresses
2. Set/export PRELINK_TIMESTAMP to a reproducible value.
If REPRODUCIBLE_TIMESTAMP_ROOTFS is specified, then the value will
be used. Otherwise the timestamp will be derived from the top git commit.
Signed-off-by: Juro Bystricky <juro.bystricky@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
