[arch] Building for the AMD64 from a 32-bit processor

[RedShift]

Hi all,

I'm going to try building current for the AMD 64 architecture. I 
currently don't have a 64 CPU, so builds can't be tested by myself. But 
I was wondering if it was possible to build a x86_64 binary from a 32 
bit machine? I would do this on a dual p-III 866.

I've already mailed Judd for this, but he hasn't replied (yet), probably 
busy doing other stuff.

This is what my makepkg.conf would look like:

export CARCH="AMD64"
export CHOST="amd64-pc-linux-gnu"

export CFLAGS="-march=amd64 -O2 -pipe"
export CXXFLAGS="-march=amd64 -O2 -pipe"

#export CFLAGS="-mcpu=amd64 -O2 -pipe"
#export CXXFLAGS="-mcpu=amd64 -O2 -pipe"

export MAKEFLAGS="-j 2"
export USE_FAKEROOT="y"
export USE_COLOR="n"
export PKGDEST=/home/glenn/build/archlinux/packages/

Is this right? For the kernel, I would use the same configuration file. 
For all the packages I won't make any modification to their pkgbuild's.

Then I would do makeworld /home/glenn/build/archlinux/packages base