[RFA/python:1/2] Add support for --with-pythondir.

[Joel Brobecker]

> I do think that we should allow for the possibility of having gdb
> python modules implemented as .so's.

Sure.  The easiest seems to add support for that on top of what's
currently been proposed when the need arises.  AFAICT, It looks like
all we have to do to make it work is add the lib-dynload directory
to the sys.path.

> For reference sake, --with-python-prefix is a worse name now.
> Setting aside --with-python=yes, the preferred parameter is the name
> or path of the python binary.  We fetch the needed parameters via
> distutils of that binary. [Setting aside cross-compilation.]

Hmmm, yes, that's right.

Let us know if you still have some concerns...

-- 
Joel