i386/x86_64 biarch toolchain on Fedora

[satyam]

Hi,

commit bb33421dde79f9a36d5485c56335ff178ac7d268 to mainline made
it possible to compile x86_64 kernels on i386 systems with simply:

$ make ARCH=x86_64

for distros that provide / support i386/x86_64 biarch toolchains (gcc,
glibc, binutils, the works), i.e. without needing to install a separate
x86_64 toolchain and then feed it to kernel make as
CROSS_COMPILE=. However, FC5 by default (at least on my box)
does not seem to provide these, gcc -m64 yields
"sorry, unimplemented: 64-bit mode not compiled in".

Does Fedora provide said biarch packages?

What do I yum-install / update / etc do to get and enable the same?

[ Yes, I know biarch toolchains could increase time / memory complexity
even for native 32-bit builds, but I'm willing to live with the same than
having to install separate toolchain, thus wasting space. ]

Thanks,
Satyam

[GregLee]

In the x86_64 edition of FC6, which I'm using, applications get compiled (and linked and run) in 64 bits by default. I haven't yet tried compiling a kernel or compiling something in 32 bits.