Avoid collisions between parallel installations of Cygwin

[Earnie Boyd]

Quoting Christopher Faylor <cgf-use-the-mailinglist-please@cygwin.com>:

>
> I don't think MSYS is a strong example.  I doubt that MSYS has a tenth
> of the popularity of Cygwin.  It certainly isn't as actively developed.
>

The phrase "actively developed" isn't the same as "actively used".  I  
know of at least 3 or 4 distributions of MSYS that put the system  
underneath their own directories.

> We often see people confused about which version of Cygwin in the
> mailing list even when there is no "cygwin version mismatch" error.
> Since the proposed change removes the error, I think that we'll now
> likely see more confusion like "I installed the latest version to fix
> problem X but it is still there!" And, we'll likely have issues where
> the cygwin from directory A creates a file with permissions slightly
> different from the cygwin in directory B.  Or the pipes used by one
> version of cygwin differ slightly from the pipes used by another.
>

That possibility exists of course but how likely is it to happen?  Out  
of the thousands of posts in Cygwin mail list, how many are confused  
about the versions being mismatched?  And with this change how will  
that figure change?  I'm guessing that there will be no more and no  
less difference in the confusion.

> But, anway, the meta issue that really troubles me is that, AFAIK,
> Corinna has always agreed with the
> one-Cygwin-per-system-unless-you-know-what-you're-doing rule.  It was
> complete news to me that she thought this was a good idea when I first
> heard about it.  If I had known she thought it was a good idea I would
> have certainly thought twice about the policy.
>
> The ability to run multiple versions of Cygwin has been in the DLL for a
> while.  I put it there.  Corinna added a lot in her patch to make it
> more solid but her change is no technological breakthrough (I'm not
> saying that she is claiming that it is).  We could have always have been
> doing this.  As far as I know, the only reason that we weren't doing
> this is because we had a policy against it.
>

And it was that code that led me to make it policy for MSYS to allow  
it to happen.

> The proposed change is coming about because someone wanted to pay for
> it.  So, it seems like, for the second time, we're talking about
> allowing a Red Hat customer to set policy for the Cygwin open source
> project.  I think that maybe everyone but me takes it as a given that
> this should be allowed but I think it is a slippery slope.  It certainly
> does make it hard for me to be a co-project lead if I can't come to a
> decision and know that it will stick.
>

I know that paying customers talk louder than the non paying ones but  
this *is* a selling point for MSYS vs Cygwin, "actively maintained" or  
not.  And the more Cygwin begins to look like MSYS the happier I am.

--
Earnie