sample@yoma ~ $ /usr/sbin/crossdev -t help
Supported Architectures:
   - alpha                                     - arm / armeb
   - hppa (parisc)                             - ia64
   - i386 / i486 / i586 / i686 (x86)           - m68k
   - mips / mipsel / mips64 / mips64el
   - powerpc (ppc) / powerpc64 (ppc64)
   - sparc / sparc64                           - s390 / s390x
   - sh / sh[1-5] / sh64                       - x86_64 (amd64)
Supported C Libraries:
   - glibc (gnu)
   - klibc       [prob wont work]
   - newlib      [bare metal/no operating system]
   - uclibc      [not all arches are ported]
Special Targets:
   - avr      http://www.nongnu.org/avr-libc/
   - bfin     http://blackfin.uclinux.org/
   - h8300    http://h8300-hms.sourceforge.net/
   - mingw32  http://www.mingw.org/
   - msp430   http://mspgcc.sourceforge.net/
   - nios2    http://www.altera.com/products/ip/processors/nios2/ni2-index.html
   - xc16x    http://www.infineon.com/
   - ee / iop / dvp (ps2) [Playstation 2 targets]
   - ppu / spu (cell) [Cell/Playstation 3 targets]
Softfloat toolchains:
   Include 'softfloat' in the 'vendor' field
   e.g. armeb-softfloat-linux-uclibc  powerpc-booya_softfloat-linux-gnu

sample@yoma ~ $ /usr/sbin/crossdev 
Usage: crossdev [options] --target TARGET

Options:
    --b, --binutils ver   Specify version of binutils to use
    --g, --gcc ver        Specify version of gcc to use
    --k, --kernel ver     Specify version of kernel headers to use
    --l, --libc ver       Specify version of libc to use
    -C, --clean target    Uninstall specified target
    -b, -d, -p, -v, -q    Options to pass to emerge (see emerge(1))
Stage Options:
    -s0, --stage0         Build just binutils
    -s1, --stage1         Also build a C compiler (no libc/C++)
    -s2, --stage2         Also build kernel headers
    -s3, --stage3         Also build the C library (no C++)
    -s4, --stage4         Also build a C++ compiler [default]
Extra Fun (must be run after above stages):
    --ex-only             Skip the stage steps above
    --ex-gcc              Build extra gcc targets (gcj/ada/etc...)
    --ex-gdb              Build a cross gdb

Target (-t):   takes the form: ARCH-VENDOR-OS-LIBC
    Run 'crossdev -t help' for examples