Fix #286600: Use same dependencies for MinGW as are used for MSVC

[Jojo-Schmitz]

works for compile, i.e. the header files are found and also for make install, i.e. the dlls are found and copied/renamed onto the instal folder (win32install or win64install), but not yet at link time, i.e. the libs are not found at that step, help needed there...

Edit: I think I got it now (basically thanks to the hint that MinGW doesn't need the static libs)

[anatoly-os]

Mingw doesn't need static libs. It somehow generates it by itself. Need to check to give more details.

Btw, FYI, I'm implementing WinSparkle which won't work with mingw from the box. It means autoupdating won't be supported from the box.

[Jojo-Schmitz]

Mingw doesn't need static libs. It somehow generates it by itself. Maybe that is why the linking takes so long?

Well, for self-built version WinSparkle won't be needed anyhow ;-)

[Jojo-Schmitz]

Esp. helpful when switching between Qt versions (like from 5.9.x to 5.12.2, which does again provide a 32bit MinGW), as all dependencies are in one place rather than scattered about in Qt directories and need to get copied across to a different Qt/Tools directory time and time again.
And there are still some 'die-hards' prefering QtCreator/MinGW over MSVS/VC...
Doesn't affect anybody else as far as I can see.
In any case: it clearly is the cleaner solution.

[Jojo-Schmitz]

See also https://musescore.org/en/node/286600

[dmitrio95]

Looking through the changes, it seems they indeed should not change anything that worked previously for all compilers except MinGW. Still I didn't pay much attention to MinGW changes, but if they work correctly I see no reasons not to merge them (especially given that MinGW seems to be considered unsupported officially).

Also after these changes the MinGW compile instructions in Handbook will need an update. @Jojo-Schmitz, will you do such an update?

[Jojo-Schmitz]

Yes, I'll update those instructions

[dmitrio95]

OK, then let's merge it, I hope it helps MinGW users.

[Jojo-Schmitz]

Thanks, https://musescore.org/en/handbook/developers-handbook/compilation/compile-instructions-windows-mingw-git is updated.