CI: setup 32-build linux build on travis

[jreback]

so if anyone is interested: https://github.com/matthew-brett/multibuild/tree/7abbd01f230be6067842f0510a98b06a6320ddf9

hosts the builder for the wheels, it does a 32-build on linux via a docker image. So we could just directly pull that same image and build (of master).

cc @matthew-brett

xref #13584

[jorisvandenbossche]

Two options:

• Using docker on Travis or Azure: basically what is explained above in the top post (and also a plan in scikit-learn: Add travis configuration to run the tests on 32 bit linux scikit-learn/scikit-learn#9352, there is a PR there that could be used as inspiration)
• Azure does possibly support 32bit builds directly? (to check)

[gfyoung]

Azure does possibly support 32bit builds directly? (to check)

@jorisvandenbossche : My guess is probably not, but couldn't hurt to check.

@datapythonista : Who was your contact at Microsoft regarding Azure builds?

[datapythonista]

@gfyoung I got most of the help when moving things to Azure from @vtbassmatt. Opening a ticket to Azure support also was useful (did that to see if they could increase the number of concurrent jobs).

[gfyoung]

@datapythonista : Cool, thanks!

@vtbassmatt : Does Azure have support for 32-bit testing environments?

[vtbassmatt]

We don't offer hosted 32-bit environments but we do ship a 32-bit Windows and Linux agent. You can set up private agents with that.

…

On Mon, Jan 28, 2019 at 10:47 AM gfyoung ***@***.***> wrote: @datapythonista <https://github.com/datapythonista> : Cool, thanks! @vtbassmatt <https://github.com/vtbassmatt> : Does Azure have support for 32-bit testing environments? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#13715 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AArmKyDojr89Xtc_TRTZY5QGaoD-oHBrks5vHxuEgaJpZM4JQpDk> .

[gfyoung]

@vtbassmatt : That's good to know. Thanks!

[jbrockmendel]

we've got a 32 bit build on azure. closeable?