[PATCH] Add initial support for SOURCE_DATE_EPOCH

[Jon Turney]

On 08/09/2023 15:09, Corinna Vinschen wrote:
> Jon,
> 
> you did all the latest work in terms of the build machinery.
> Would you mind to review this patch, please?

Sure.

Patch looks all right to me, so I applied it.

> On Sep  5 19:01, Christian Franke wrote:
>> This patch enables reproducible builds of cygwin package in conjunction with
>> this cygport patch:
>> https://sourceware.org/pipermail/cygwin-apps/2023-August/043108.html
>>
>> cygwin.cygport was enhanced for the test as described in the above post.
>>
>> If the same build path, SOURCE_DATE_EPOCH and toolchain are used, rebuilds
>> with cygport produce identical distribution tarballs. Adding proper
>> -fmacro-prefix-map gcc options (or remove all usages of __FILE__) could
>> possibly make this independent from the build path.
>>
>> Note that 'u' (replace with newer objects only) flag needed to be removed
>> from ar commands because it is incompatible with 'D' (deterministic
>> archive). I don't expect any negative effect because existing .a files are
>> always removed before ar is run.
>>
>> Not yet tested with different machines or different users accounts.
>>
>> Patch would be much simpler (mkvers.sh only) if binutils would support
>> SOURCE_DATE_EPOCH directly.
>>