Compiling gcc in 64 bits mode

[lol37 lol37]

Hello everybody,
now that i know and compiled with success gcc, i wonder how i can make
a gcc compiler for 64 bits platform, is the compiliation process is
the same except that extras flags are involved, and if yes, which ?
i've looked on the net for binutils i found --enable-64-bit-bfd,
--host=x86_64-mingw32 and also for --target
is there any other flags for gcc dependencies ( like gmp, mpfr, mpc,
pthread ... ) ?
Thanks for all.
Sam.