__DATE__, __TIME__ and __TIMESTAMP are part of the standard predefined macros of the C pre-processor.

Now that GCC has accepted our patch to support SOURCE_DATE_EPOCH, __DATE__ and __TIME__ will instead use that deterministic value, and package maintainers shouldn't need to do anything extra to make their builds reproducible.

We missed out __TIMESTAMP__ by mistake, but we will probably send in another patch to GCC to fix that.

Known affected packages - this should soon drop in number as we rebuild things with the newer GCC. However there are still some packages using __TIMESTAMP__.