gdbserver-external: don't package libstdcxx gdb python bits

gcc-runtime will be handling that.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
eglibc-external: kill duplicated headers subdirs in FILES

The libc ${includedir}/*/ are already listed in libc.headers.

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Consolidate todos, drop unused path_extract

Signed-off-by: Christopher Larson <chris_larson@mentor.com>