$tooldir

[Jeffrey A Law <law at hurl dot cygnus dot com>]

I'm sure y'all both remember the tooldir problems I introduced back in
Sept/Oct.  Thanks to you we managed to get them _mostly_ sorted out.

However, in the process, we killed the entire point behind the changes I made.
So, time to re open this can-o-worms.

The core issue is we want to be able to use a directory relative to $libsubdir
which gets us to $tooldir.  This is one of the important changes needed to
allow the gcc hierarchy to move around without needing to fiddle with -B args
or setting GCC_EXEC_PREFIX.


First requirement is we do not want to hose $tooldir uses in other Makefiles
outside of gcc -- consider a naked gdb installation we can't reference
$libsubdir because it is specific to gcc installations.

  * Thus, We do not want to change the toplevel tooldir specification, nor do
    we want to remove it from flags to pass.

  * Therefore, gcc must not use tooldir, it'll have to use a different name.
    $(gcc_relative_tooldir) or something like that.


We also do not want to hose configurations which explicitly specify locations
for tooldir or libsubdir.  For simplicity, we can avoid this if $tooldir
looks like anything other than $prefix/$target_alias or libsubdir looks like
anything other than $prefix/$libdir/gcc-lib/$target_alias/$target_version.
For that case we'll just use the $tooldir value provided by the toplevel
configury/Makefile machinery.

Am I missing any other issues?

jeff