[FFmpeg-devel] Fixing configure on Solaris

[Dave Dodge]

On Fri, Aug 10, 2007 at 01:05:59AM +0300, Jan Knutar wrote:
> On Friday 10 August 2007 00:47, Roman Shaposhnick wrote:
> 
> >   Now, that, of course is a poor excuse for NOT having a system that
> > is flexible enough to ask anybody installing a simple question:
> > "Are you an old geezer? [Yes/No]" and have "No" as the default ;-)
> 
> I read man standards and put the sane $PATH in my login script...

That still has the downside that when a script changes the path or
invokes /bin/grep directly, they get the "wrong" version.

Aside: Back in the 80s Apollo (one of Sun's competitors) took the
approach of using variant symlinks.  Top-level system directories such
as "/bin" were symlinks to something like "/$(SYS)/bin", where SYS was
expanded on the fly from an environment variable.  This allowed them
to provide BSD4.2, BSD4.3, SVR3, and their own Aegis toolsets, all on
the same machine at the same time.  A script run with SYS set to
"bsd4.3" would get BSD4.3's grep even if it explicitly invoked
"/bin/grep".

Of course there were security issues with this sort of approach,
because SYS has to be handled as carefully as PATH when running
anything with elevated privileges.

Dragonfly BSD has variant symlinks but I haven't kept up with how
their implementation works.

On Linux you could probably mimic something like this by combining
namespaces and bind mounts, though it would probably really confuse a
lot of users.

                                                  -Dave Dodge