Vega-strike-engine-source: Travis-CI: Enhancements

[BenjamenMeyer]

Travis-CI has been integrated to do PR gate checks. It presently only supports a few of the Linux distros, Ubuntu versions at that. Update the Travis-CI configuration to support the following:

• [ ] Ubuntu 18.04
• [ ] Ubuntu 20.04
• [ ] CentOS/Fedora Version ????
• [ ] Mac OS 10.15 (Catalina)
• [ ] Windows 10

Additional Possible Versions:

• [ ] Mac OS 10.14 (Mojave)

If this is not possible with Travis-CI, then is there an open-source project friendly and no cost CI system that can support these platforms? If not, we may need some community members to do periodic testing on supported platforms that can't be PR gated.

[BenjamenMeyer]

Looks like Mac OS X is supported by Travis-CI.

• https://docs.travis-ci.com/user/reference/osx/
• https://docs.travis-ci.com/user/multi-os/
• Limited to 10.14 right now; no support for 10.15. That's probably okay for now.

Looks like Windows support is still experimental by Travis-CI:

• https://docs.travis-ci.com/user/reference/windows/

I suggest we start adding both the Windows and MacOS support to what we can, and allow them to fail for the time being. As Travis-CI matures and as we mature the config we can move to requiring them to pass.

[BenjamenMeyer]

I've figured out OSX. I can match all our dependencies to brew installations so we should be okay; will see once I get the PR up.

Windows support is going to be harder. The package manager Travis is using for Windows (chocolatey.org) only has the following packages that match up with our dependencies:

• python2
• openal, openalsdk

We're probably going to have to just vendor stuff for Windows or add support to Chocolotey if we wanted to use that. The Windows support is still very very lacking; enough that it's not worth adding yet. Errors when trying to test using the https://config.travis-ci.com/explore:

• Doesn't recognize windows as an OS
• Doesn't recognize choco or chocolatey as an addon

It'll be a lot of custom work to support Windows right now. Let me get the Mac OS X support up and then we can see about Windows in a later PR.

[BenjamenMeyer]

Added #43 which adds some more OS configurations, namely Ubuntu 18.04 and OS X.

OS X builds are allowed to fail right now, which is good b/c they are. More work is needed to get it fully working but that PR at least builds the foundation.