Config updates

[Nicola Pero]

I committed some changes to gnustep-make that should fix a few remaining
issues
in the config system.  There are a few things worth nothing.

**1. No more need to source GNUstep.sh :-)

It works for me, might need more work to work for everyone I guess ;-)

Anyway in the standard flattened/no-multi-arch case, once I add the
gnustep dirs
to /etc/ld.so.conf and to PATH (I'm on GNU), I can now compile stuff by
just doing:

export GNUSTEP_MAKEFILES=/opt/gnustep/System/Library/Makefiles
make

No more need to source GNUstep.sh :-)
(hope it works for you as well, if not, let me know!)

This is now pretty much how every other unix stuff is compiled and ran,
except for the custom
installation location that we use. ;-)


**2. Each library-combo needs to be configured separately

Second, Richard started a change to move the gnustep-make config into a
library-combo subdir,
which I've now completed ... it has a few implications:

 1. you can configure different library-combos to use different compilers
with different flags;
I assume this was the main reason behind the change (presumably it helps
with apple-apple-apple
vs gnu-gnu-gnu on Mac OS X ?)

 2. if you haven't configured a library-combo, you can no longer use it. 
For example, if you plan on
using both gnu-gnu-gnu and gnu-ld-nil, you need to do

         ./configure --with-library-combo=gnu-gnu-gnu --disable-flattened
         make
         su -c 'make install'

         ./configure --with-library-combo=gnu-ld-nil  --disable-flattened
         make
         su -c 'make install'

The second one is needed because it will install
GNUSTEP_MAKEFILES/ix86/linux-gnu/gnu-fd-nil/config.make.
If you try to compile using a library-combo that wasn't configured, it
won't work.  This is because
each one has got its own CC, OPTFLAGS, etc flags now.  Hmmm.

By the way, compiling with only GNUSTEP_MAKEFILES seems to work for me
even in the unflattened case. ;-)

Thanks