Re: configure's checks for --enable-tap-tests are insufficient

On 2018-03-20 17:23:26 +0000, Dagfinn Ilmari Mannsåker wrote:
> Tom Lane <tgl@sss.pgh.pa.us> writes:
> > That seems like expensive overkill to me, especially since it seems
> > unlikely that we'd keep the list up-to-date over time. 
> 
> The patches uptread add about 0.2s to a 6.9s configure run here, I don't
> consider that very expensive.  We don't add new modules very often, so I
> don't think it's much of a maintenance overhead either.

Not huge, but also not nothing. But I think if we care we could make
this cheaper fairly easily? I don't think there's any need to invoke
perl one-by-one for each module. Should be trivial to have perl report
back all the modules it's missing from a list of arguments.

It's also certainly annoying that AX_PROG_PERL_MODULES doesn't support
caching. I'm not sure we're benefiting much from using the AX* script
here.

Greetings,

Andres Freund