TODO: remove some items

Those items have now been implemented:

- mingw32 target
we have it now, and even mingw64 too

- mingw32 host
it is certainly possible to canadian-build a toolchain to run
in a mingw host

- Cygwin host
it is possible to build a toolchain in Cygwin, and it is probably
possible to canadian-build it as well

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 #!/bin/sh

 call_to=@@DEFAULT_LD@@

 case "${CTNG_LD_IS}" in

     bfd)    call_to=bfd;;

     gold)   call_to=gold;;

 esac

 exec "${0}.${call_to}" "$@"

 exit $?