gmp/mpfr - build, host, or target?

[NightStrike]

On 2/17/08, Brian Dessent <brian@dessent.net> wrote:
> NightStrike wrote:
>
> > The gcc build system, when building gmp and mpfr in the gcc source
> > tree, will send a --target option to the configure script of gmp and
> > mpfr.  If gmp is only used for the host system, why is this?  I
> > checked the GMP manual, and I don't think target even applies:
>
> Are you sure you're not just getting confused by the fact that all
> arguments supplied to the top level configure script are passed on to
> all sub-configures?  There is nothing that I can see that would add
> --target, other than the fact that you're probably supplying it at the
> toplevel.  I don't see how this matters anyway, as --target for a
> regular library is ignored.

I might be getting confused, but I don't think so (obviously, or I
wouldn't be posting).  This is what I see in Makefile.def:

host_modules= { module= gmp; lib_path=.libs; bootstrap=true;
                extra_configure_flags='--disable-shared';
                no_install= true;
                host="none-${host_vendor}-${host_os}";
                target="none-${host_vendor}-${host_os}"; };
host_modules= { module= mpfr; lib_path=.libs; bootstrap=true;
                extra_configure_flags='--disable-shared
--with-gmp-build=$$r/$(HOST_SUBDIR)/gmp';
                no_install= true;
                host="none-${host_vendor}-${host_os}";
                target="none-${host_vendor}-${host_os}"; };