liste of available cross-compilation targets (--build)

[#Cyrille37#]

Hello
I do not remenber how to retrieve the list of configure targets for 
cross-compilation (--build).

I usually compiling gmp on windows with cygwin with the command :
../gmp-4.2.2/configure CC="gcc -mno-cygwin" \
    --build=core2-pc-cygwin --host=i686-pc-mingw32 \
    --disable-static --enable-shared

now I've to compile for a Windows 64bits target. Do you know the --build 
value ?

Thanks a lot
Cyrille.