Test ppc64el on Travis

[nikic]

Travis also supports ppc64el architecture: https://docs.travis-ci.com/user/multi-cpu-architectures/

We should test it, and drop one of our amd64 jobs instead.

[nikic]

Work in progress: php/php-src#5791

[nikic]

I guess this is a moot point now that we no longer use Travis.

It would be nice to find a new way to test on non-x86 architectures.

[kocsismate]

Apparently, there is a GitHub action for this: https://github.com/marketplace/actions/run-on-architecture

[nikic]

Yeah, I found that one as well. It's based on qemu, so maybe slow... Probably worth giving it a try though. At least arm64 seems like something we should be testing.