patches/gdb: Fix canadian building of GDB for powerpc

Adds patch for GDB v6.8, v7.0, v7.0.1 to fix canadian
cross building of GDB for powerpc.

See original patch information here:
http://sources.redhat.com/bugzilla/show_bug.cgi?id=9638

The patch is not required for GDB v7.1 (fixed).

Tested in canadian combination using mingw32 and powerpc toolchains.
Tested to not affect normal cross building of GDB for powerpc target.

Signed-off-by: Martin Lund <mgl@doredevelopment.dk>

# Dummy config file to not use a C library *at all*

# depends on BARE_METAL

config LIBC_none

    help

      Do not use a C library.

      This is usefull if your project is self-contained, does not rely on

      an external C library, and provides all the necessary bits.

      Most probably usefull to bootloaders, as they generally don't depend

      on the C library.

      If unsure: do *not* choose that, and use another option in the choice.