debug/gdb: new option to enable/disable use of python

Add a new option to enable/disable the Python scripting in gdb.
Hide the option (ie. disable it) when statically linking the cross-gdb.

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

 reporter_name="Remy Bohmer"

 reporter_url="linux@bohmer.net"

 reporter_comment="Example for building a toolchain for m68000 bare metal targets"