/usr/local question

[Jan Stary]

On Apr 04 10:34:48, Jeremy Lavergne wrote:
> > Yes, that's what I have read. But that just says why macports
> > uses /opt/local: because it cannot use /usr/local, for the reasons listed.
> > 
> > This here is something *different*: namely, that
> > 
> > (1) There might still be problems if the user has /usr/local around.
> 
> 	? Some software (especially auto* tools from Gnu) look in /usr/local as a default location
> 	? /usr/local tends to be a bad choice to have taken over by a non-system port system
> 	? gcc considers /usr/local to be a standard system directory, causing (at least) the include directory to be unable to appear early in the list of include directories, and hence causing MacPorts-installed items to be difficult to use properly for items which need them (where another version is installed elsewhere, like/usr/X11R6)

Yes; I _have_ read it. The FAQ lists these as the reasons
why macports uses /opt/local as its prefix.

Perhaps I need to state my comment more explicitly:
there are TWO DIFFERENT issues:

(1) It would be a problem if macports used /usr/local
as its prefix; so it doesn't - it uses /opt/local instead

(2) Even with macports using /opt/local as its prefix,
it is STILL A PROBLEM to have /usr/local around.

The link above talks about (1), but not (2).

> It isn't explicitly stated but it is implied.

No it's not; on the contrary, it is implied that
using the prefix of /opt/local instead of /usr/local
SOLVES the three issues listed above, which it does not.

In fact, I believe it is a good candidate for a FAQ immediately
following https://trac.macports.org/wiki/FAQ#defaultprefix:

Q: "So given that macports uses /opt/local as its prefix,
I can use /usr/local freely without worying about interference?"

A: No, not really. (etc)