Allowing PortGroups to bump port revision

[Clemens Lang]

Hi,

On Sun, Jan 14, 2018 at 12:01:34AM +1100, Joshua Root wrote:
> portindex isn't slow, mportopen is. You have to evaluate the changed
> Portfiles before you can extract their info.

I haven't measures this, but I assume the majority of time in mportopen
is spent by the sub-interpreter loading the port1.0 package (i.e.
evaluating the PortSystem 1.0 line in the Portfile). Since this set of
files should be in the buffer cache after the first Portfile was
evaluated the problem is probably not the disk speed.

This could be made much faster if Tcl had a way to 'clone' an
interpreter that already had port1.0 loaded before running the rest of
the Portfile. If somebody wants to implement that, that would probably
improve portindex speeds significantly.

-- 
Clemens