[RFC] Proposal for hosting GDB CI builds

Hi,

This proposal comes as an attempt to revive the GDB CI builds, given the 
previous one (buildbot) is no longer being maintained by Sergio (thanks 
a lot for keeping it working for all these years by the way).

CI GDB builds are a great help for spotting regressions without having 
to do the tedious and time-consuming work of running the GDB testsuite 
for each git revision, for each architecture and reading through 
hundreds of lines of summaries. If a regression is spotted, then one 
needs to bisect to find the culprit. This isn't great, specially for 
architectures without great availability of desktop hardware.

Ideally, for each commit, we'd run full builds to validate the state of 
the tree, but we're not quite there yet. So meanwhile, having some level 
of automation to get the builds done without manual intervention sounds 
like a reasonable step forward.

 From previous IRC conversations, it seems to be a consensus that 
availability of processing power is not a problem. It is reasonably easy 
to find hardware to do some builds. The most difficult resource to find 
is manpower to setup the CI infrastructure and keep it running.

With the above said, I've discussed this internally at Linaro and we can 
spare some manpower to setup and maintain an isolated Linaro-hosted 
Jenkins instance for GDB CI builds.

Linaro can take care of providing builders and build jobs for ARM. Other 
architectures would be handled by their respective contributors. Those 
contributors can write jobs and plug builders as needed.

Setting up new jobs doesn't require the use of the web interface. It can 
be done with yaml files in a git repo. It is reasonably simple.

You can see an example of the Linaro CI here: https://ci.linaro.org/

Also, a GDB job for aarch64: https://ci.linaro.org/job/tcwg-gdb/

And also the summaries for GDB testsuite runs: 
https://ci.linaro.org/job/tcwg-compare-results/13968/artifact/artifacts/logs/0-report.html

Of course, this effort only makes sense if the community is OK with 
using Jenkins as the CI mechanism and if it actually sees value in 
having a system like this in place.

Thoughts? Questions?