Upgrade c++ standard from gnu++0x to c++17

[nyllet]

Make sure it builds for mingw. The WIN32 macro appears not to be set when building for mingw. However, MINGW32 is set for both 32-bit and 64-bit

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[nyllet]

#5145 must be merged before this one, otherwise the macos builds will fail

[deveee]

I'm not keen to make such changes because I don't see real benefit and it usually breaks compilation. For example I build linux package using old debian for better compatibility.

[CodingJellyfish]

Is there any progress on this? If not I guess I should close this.