[Bf-committers] Retiring Linux GLibc 2.11 builder

[Sergey Sharybin]

Hi,

= Summary =

Our release environment which is based on glibc-2.11 is getting far too old
and unmaintainable and already causes major problems getting some branches
to compile.

I plan to discontinue this builder with the next round of dependencies
update.

The default (and only) supported glibc version will be 2.19 (and above).

= What does this mean for users =

For users it means their Linux box should have glibc-2.19 on their system.
It doesn't seem to be a problem in model distros, because this libc version
was released in 2014 and all major distors picked it up.

Basically, everyone on Ubuntu 14.04 and above should be safe. Current
Debian stable is also safe and ready for such update.

New release environment also has much newer compiler, which hopefully gives
some %% of speedup.

= How to check whether required GLibc version is installed? =

Most reliable test is to run `ldd --version` and see if gives version 2.19
or above.

If ldd is not installed, then something like this should work:

- For 64 bit systems: /lib/x86_64-linux-gnu/libc.so.6 --version
- For 32 bit systems: /lib/i386-linux-gnu//libc.so.6 --version

= Can such bump be avoided? =

In theory, in practice i didn't find a way to limit Blender to only use
older libc functions. This is also not really fun, because even if we can
tell Blender to only use older libc symbols, we still link against
non-self-compiled libraries which seems would also need to be recompiled.

However, if someone knows easy way for us to deliver more portable builds
from a newer Linux we are fully open to learn that.

= Any possible regressions? =

There should be no regressions. All the known and reported issues were
fixed already and we already deliver 2.78 release builds for glibc-2.19
(next to glbc-2.11).

-- 
With best regards, Sergey Sharybin