further changes - request for comments

[Nicola Pero]

This is all tentative brainstorming, but I'd like comments if you have.

Since we are discussing any sort of filesystem
rearrangements/simplifications, it came to mind that we could simply the
non-flattened case by replacing

/ix86/linux-gnu/

with something like (tentative example)

/ix86-linux-gnu/

That would simply the 3-layer directory structure

/ix86/linux-gnu/gnu-gnu-gnu/

into the simpler 2-layer one

/ix86-linux-gnu/gnu-gnu-gnu/

It's the same information, but it's easier to navigate on file browsers
(or on the command-line if you use completion).

I know we're theoretically loosing a bit of flexibility (you could no
longer install stuff in a directory which is processor, but no os,
dependent), but as a matter of fact in the whole history of gnustep we've
never used this flexibility, and simplifying the layers would be great.

Because the other change is that now after speaking to Richard, it seems 
that maybe a good idea would be, for the non-flattened/power-user case, to 
have the Headers/ directory match exactly the Libraries/ directory, as in

  Headers/ix86/linux-gnu/gnu-gnu-gnu/xxx
Libraries/ix86/linux-gnu/gnu-gnu-gnu/xxx

that way, GSConfig.h in gnustep-base could be simply installed with the
other headers as it would be installed in a cpu/os specific directory.

At the moment instead it is installed into the special directory

  Headers/gnu-gnu-gnu/ix86/linux-gnu/GSConfig.h

which is not only confusing (compared to libraries, where gnu-gnu-gnu is
*after* ix86/linux-gnu), but it requires another set of -Ixxx on the
command line to get into the ix86/linux-gnu directory; we'd also like to
install GSConfig.h inside GNUstepBase to enforce making it easily
"frameworkable" on OSX.

I'd love this change because than I can drop yet another set of -Ixxx on
the command line :-)

In other words, changes proposed are:

 * replacing /ix86/linux-gnu/ with /ix86-linux-gnu/

 * installing all headers in Headers/ix86-linux-gnu/gnu-gnu-gnu/xxx which
matches the Libraries/ix86-linux-gnu/gnu-gnu-gnu/xxx directory, and means
you don't need to install cpu/os specific headers in a separate directory.

 * removing -Ixxx/ix86/linux-gnu/ from the command line.

The flattened case is unchanged, except potentially GSConfig.h, which
should at the moment go in Headers/ix86/linux-gnu/GSConfig.h (and which
would end up being top-level in the flattened case then!), would be moved
into Headers/GNUstepBase/.

(I'm not sure what temporary solution David used for GSConfig.h, but it
must be installed into a cpu/os-dependent directory, and the only at the
moment in headers is xxx/Headers/ix86/linux-gnu/).

Thanks.