cache variable documentation (was: Autoconf and Automake support for ObjC++)

[Ralf Wildenhues]

* Peter Breitenlohner wrote on Tue, Jul 21, 2009 at 11:26:15AM CEST:
> During the last several months I was involved in a complete rewrite of
> the TeXlive (formerly teTeX) build system using Automake and modernized
> Autoconf.
> 
> In doing so I "had" to use the names of various cache variables, in order to
> write, e.g.
[...]
> It would be nice if these ac_cv_* names could be made part of the API, i.e.,
> be frozen and documented.

This has been done recently, for many cache variables.  I failed to see
this message at that time (wrong Subject ;-) so didn't list you as bug
reporter.

Cheers,
Ralf