Re: [gentoo-user] Re: GCC 5.4.0

[Mick]

On Monday 24 Apr 2017 08:57:26 Neil Bothwick wrote:
> On Sun, 23 Apr 2017 17:29:28 -0700, Ian Zimmerman wrote:
> > What I hope for is a way to selectively download only the gcc-5 ebuild
> > and its depndencies, which I could temporarily put in a separate local
> > repo.  Then, if the gcc update goes OK, I can move them in the normal
> > portage tree and go ahead with the rest of the update.
>
> PORTDIR="/somewhere/else" emerge --sync
>
> should give you a new copy of the portage tree without touching the
> original.
>
> You may be overthinking this, I have no recollection of the gcc-5.4.0
> update which means either there was nothing to remember or I'm losing the
> plot. I hope it is the former. That includes installing it on stable
> systems that run testing gcc to make use of distcc easier.
>
> gcc is slotted so you will still have 4.9 available should anything go
> wrong. You can potentially get build failures with a gcc upgrade but that
> won't affect your installed software, so it's an inconvenience rather
> than a problem.

I'm with Neil here, I think you are labouring over a process that portage will 
mostly take care of itself.  As others have already suggested;

1. Emerge the new gcc:

emerge -uaDv gcc

2. List available gcc versions:

gcc-config -l 
[1] x86_64-pc-linux-gnu-4.9.4 *
[2] x86_64-pc-linux-gnu-5.4.0

3. Select the new gcc version:

gcc-config 2
gcc-config -l 
[1] x86_64-pc-linux-gnu-4.9.4
[2] x86_64-pc-linux-gnu-5.4.0 *

4. Source the new profile:

. /etc/profile

5. Rebuild all packages that have a dependency on libstdc++.so.6':

revdep-rebuild --library 'libstdc++.so.6' -- --exclude gcc

6. Clean old versions of gcc you no longer need:

emerge --depclean -a -v


NOTE:  If some program fails to emerge on step 5 continue with 'emerge --
resume --skip-first' and make a note of the package that failed to emerge.  
When step 5 finishes manually emerge the previously failed packages with 
'emerge -1aDv <package_1> <package_2>'

I hope I haven't forgotten any steps above, but if you run into trouble post 
back with specifics.
-- 
Regards,
Mick