gdb: Add missing runtime dependency for python option
With python enabled, gdb refuses to start without core
python modules:
| Could not find platform independent libraries <prefix>
| Could not find platform dependent libraries <exec_prefix>
| Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
| ImportError: No module named site
It also complains if python-codecs is missing.
Signed-off-by: Andreas Oberritter <obi@opendreambox.org> Signed-off-by: Andre McCurdy <armccurdy@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com>