Re: Using 'libfaketime' for reproducible builds

[Werner LEMBERG]

>> I definitely consider intercepting various syscalls by means of
>> LD_PRELOADing more intrusive than setting a single environment
>> variable that was invented for the purpose of setting timestamps.
>> Just think of a new shiny syscall that might add a new source of
>> non-reproducibility.
> 
> I agree with Jonas. As a further argument, LD_PRELOAD is also
> dependent on the platform; I think it wouldn't work on OSX, for
> example.

'libfaketime' works on OSX, too.  According to the documentation, you
have to do

  export DYLD_FORCE_FLAT_NAMESPACE=1
  export DYLD_INSERT_LIBRARIES=/path/to/libfaketime.1.dylib
  export FAKETIME="2020-12-24 00:00:00"

My final conclusion is that 'libfaketime' offers a nice route to get
reproducible builds with minimum effort.  `SOURCE_DATE_EPOCH` fails
miserably with gs, and making gs do what we want is hard, if not
impossible, as discussed in a previous mail.

If people want to work more on gs reproducibility issues, please do!
I won't.


    Werner