Build with Mingw-w64

Crystal is in the process of supporting Visual Studio. However Mingw-w64 should
be supported as well.

http://mingw-w64.org

[sam0x17]

I'm all for this because I like the idea of being able to build windows binaries without windows, but not to the detriment / timeliness of the current windows development being done. That said, maybe this will make windows CI easier? or no?

[straight-shoota]

Of course, Mingw64 should be supported. It doesn't feel like a pressing issue to me, though.

I don't no much about the practical differences between MSVC and Mingw64 in regards to Crystal supporting it. But, as I alread said in #5430 (comment), the current effort should focus on porting the stdlib to Win32 API. That needs to be done anyway and still requires a lot of work. Supporting an alternate tool chain doesn't gain anything until that is at least somewhat matured.

this will make windows CI easier?

Windows CI needs to run on windows anyway, so there is no point in cross compiling from a different platform.

[faustinoaq]

Windows CI needs to run on windows anyway, so there is no point in cross compiling from a different platform.

Azure CI looks very interesting. It supports Windows, Linux and Mac and is free fpr Open Source Projects: https://azure.microsoft.com/en-us/blog/announcing-azure-pipelines-with-unlimited-ci-cd-minutes-for-open-source/ @bcardiff @RX14 👀

[straight-shoota]

travis-ci has also announced windows support: https://blog.travis-ci.com/2018-10-11-windows-early-release

That should be fairly easy to integrate into the CI setup

[mominshaikhdevs]

Since Crystal is maturing support towards MSVC and Win32 APIs directly instead of mingw-w64 (#26 (comment)), Is this still relevant?