[PATCH] Add support for --with-arch configure option

[Andreas Krebbel]

Hello Roland,

> If you aren't adding new sysdeps/CPU/SUBTYPE directories in libc or a libc
> add-on, then there is no reason to use --with-cpu.  Just put whatever -mfoo
> switches you like into CC when running configure.

In fact I would like to add a CPU specific directory for S/390.  GCC for S/390
never supported -mcpu we only have the -march switch.

> We're only going to have one configure switch related to this, as Ulrich
> said.  What it does needs to work for all the supported GCC versions with
> which people build libc using --with-cpu today.  We support all since 3.4,
> though I presume there is a small subset of GCC version + machine pairs on
> which anyone needs --with-cpu to work.

I don't think a single switch will be sufficient since various targets
either support -mcpu or -march or in fact both.  Please see my
response to Ulrich.

Bye,

-Andreas-