[Cin] libaom findings, gcc/c++ and old distros

[Andrew Randrianasulu]

Well, while this may be not very good idea
(libaom.git by def. unstable target...), I looked around

https://aomedia.googlesource.com/aom/

and found new tag!

Tags
v1.0.0-errata1-avif

tag
62c211d7060ad47184d89cda7863dccbc1ace22a
  tagger
Yaowu Xu <yaowu at google.com>  Thu Dec 12 10:50:24 2019 -0800
  object
4eb1e7795b9700d532af38a2d9489458a8038233
AV1 Version 1.0.0 with errata 1 for AVIF

This tag does not indicate or imply any change to AV1 bitstream or
decoding behavior since v1.0.0-errata1, rather it indicates this
library can also be used for encoding and decoding AVIF.

Huh ..since this time  some more changes were made to git ...

including sse2 acceleration
"Add sse2 four-points sad_avg"
 "Add neon/sse2 optimization for fwd txfm 4x4
  Add unit test to verify C/SSE2/NEON are bitexact."


from this example of config line at AOM page

cmake path/to/aom \
        -DENABLE_CCACHE=1 \
        -DAOM_TARGET_CPU=generic \
        -DENABLE_DOCS=0 \
        -DENABLE_TESTS=0 \
        -DCONFIG_ACCOUNTING=1 \
        -DCONFIG_INSPECTION=1 \
        -DCONFIG_MULTITHREAD=0 \
        -DCONFIG_RUNTIME_CPU_DETECT=0 \
        -DCONFIG_WEBM_IO=0 \

I assume it can be configured with multithreaded and/or runtime cpu (simd?)
detection.

Currently building master on gcc 5.5/32 bit Slackware ....

PS; it seems Debian 8 will be ofically EOL by Debian from June, 2020:

https://wiki.debian.org/LTS
"Debian 8 “Jessie” 
  i386, amd64, armel and armhf 
  from 17th June 2018 to June 30, 2020"

BUT there might be extended support from another company ...
https://raphaelhertzog.com/2020/03/11/keeping-debian-8-jessie-alive-for-longer-than-5-years/

on CentOS7 front ... 
https://forum.qt.io/topic/111182/qt-5-14-1-won-t-compile-anything-on-my-centos-7

it seems latest qt 5 depend on same set of new c++ features as other libs, from now on ..

https://www.softwarecollections.org/en/scls/rhscl/devtoolset-7/
"devtoolset-7 - Developer Toolset is designed for developers working on CentOS 
or Red Hat Enterprise Linux platform. It provides current versions of the GNU Compiler Collection, 
GNU Debugger, and other development, debugging, and performance monitoring tools."

Ubuntu 14.04.x .... 
https://gist.github.com/beci/2a2091f282042ed20cda
gcc 5 on ubuntu 14.04

BUT with big fat warning ...
"ppa:ubuntu-toolchain-r/test
seems like it's not being updated or bugfixed properly and could even leave your Ubuntu 14.04 machine in an unbootable state. Beware...
See here a bunch of people breaking their installations of apt-get and gnome by blindly using that repo:
https://askubuntu.com/questions/777803/apt-relocation-error-version-glibcxx-3-4-21-not-defined-in-file-libstdc-so-6#"

There seems to be another PPA with gcc 8.1

https://launchpad.net/~jonathonf/+archive/ubuntu/gcc-8.1/+packages