[RFC] upgrade for helpers config.test scripts

One of the outstanding issues in ./configure has been the dependence on
standalone bash scripts for detecting whether a helper is able to build
or not.
The problem is that they are standalone so we cannot re-use test results
already existing in configure.ac in the scripts and vice-versa.
We also encounter some errors (as seen in the bugs about SASL location)
as a side effect of different tests being run.

To resolve this I propose changing the config.test files into small M4
scriptlets which can be included directly into configure at bootstrap time.

Pros:
  * we gain a huge amount of information from existing configure.ac tests
  * we gain ability to run autoconf checks in the test scriptlets
  * we can push test results back to the main configure.ac cache from
the scriptlets for faster overall process

Cons:
  * we lose the ability to drop-in third party helpers and build as if
they were part of the Squid sources.
However I am not aware of any downstream distro packagers actually
making use of this ability so it should not be a big loss.

Opinions?

Amos
Received on Mon Apr 29 2013 - 01:07:50 MDT