[gdal-dev] [Proposal] Move optional raw datasets to separate directory

[Andrew C Aitchison]

On Fri, 1 Feb 2019, Even Rouault wrote:

> (Re-adding the list)
>
>>> Is the split in 2 directories for aesthetic reasons, or because it makes
>>> the
>>> conditional compiling logic easier ?
>>
>> The latter. I'd like to avoid modifying the cpp files themselves to add
>> ifdefs to them.

Most of the drivers I have looked at have a suitable ifdef,
so I checked and was surprised to see that most do not
(a rough grep suggests that 28 frmts directories have such an ifdef and 93 
do not).

The pull-request talks about
./configure
 	... \
 	disable-driver-nnnn \
 	...

When using this proposal to generate minimal binaries, would
it not be more natural to name the drivers that you wish to *enable*
and have the configure system add whatever dependencies are required ?
When a new driver ws added, I would like to assume that my minimal
build would ignore it, without having to alter my build command.

I'm not sure about making "virt" one of the few required drivers;
it would be hard to determine which virt files would be supported
since a single target could use any of the other drivers.