[GRASS5] optional features defaulting to yes

[Glynn Clements]

Hamish wrote:

> I notice that several optional features are defaulting to yes in the
> ./configure step, leading to confusion about the mandatory prereq's are.
> 
> http://grass.ibiblio.org/grass60/source/REQUIREMENTS.html

"mandatory" means that it is required even if you disable all optional
features using --without-<package>.

> while for libpng, tcltk I can see that a default of "yes" is desirable,
> should this be true for lesser used features? 
> 
> e.g.
>   --with-postgres     support PostgreSQL functionality (default: yes)
>   --with-fftw         support FFTW functionality (default: yes)
> 
> 
> (mostly speaking of postgres here. why is it treated differently than
> MySQL?)

Enabling optional features by default has historically been a
defensive mechanism against users who basically run
"./configure ; make ; make install" then complain that the modules
which they didn't enable don't seem to work.

If we enable most things by default, and force them to disable things
manually, they're more likely to realise that the problem is due to
the feature being disabled.

-- 
Glynn Clements <glynn at gclements.plus.com>