[gentoo-osx] env.d; perl with collision-protect

[Hasan Khalil]

The Background:

Perl is almost ready for the default (collision-protect) profiles.  
I've modified the latest perl ebuild to install all binaries  
(normally installed to '/usr/bin') into another location (/System/ 
Library/Perl/${PV}/bin) to avoid collisions. No other collisions are  
created by the perl ebuild. I'll make these revisions more public  
once I can get them tested more thoroughly (I already broke Apple's  
perl on my system, accidentally of course, while working on Gentoo's  
perl). There are still a few issues to iron out.

The Issue at Hand:

One of these issues is providing Gentoo's perl as the default when  
`perl` is executed in interactive shells (bash, in my case). The  
lovely '/etc/env.d' structure lends itself to the sort of PATH  
mangling that needs to be done, but there is one problem here. '/etc/ 
profile.gentoo' appends the PATH from '/etc/profile.env' to the  
existing PATH, rather than inserting to the beginning of the existing  
PATH. This is not just an issue with perl, but also with any other  
program that we install to a different prefix and that is also  
provided by Apple in the default PATH (later down the line we should  
have prefixable installs globally supported by portage 2.1).

My Proposed Solution:

I'm thinking that we should have a variable (perhaps in some file in  
'/etc/conf.d', or perhaps just in /etc/profile before the line that  
sources '/etc/profile.gentoo') that dictates whether or not the '/etc/ 
profile.env' PATH should take precedence over the default PATH. All  
that needs to be done then is to check for this variable in '/etc/ 
profile.gentoo' and export the PATH appropriately. Of course, one of  
the most important things to do would be to document this (both in  
the revised baselayout's post-install message, as well as on the web  
somewhere).

What does everyone think?

--
Hasan Khalil
eBuild and Porting Co-Lead
Gentoo for Mac OS X