I don't have a 64-bit version to try, but the 32-bit version still works, so I'd need more info about why you're suggesting those additions before I could consider them.
Is it straightforward to install a 64-bit mingw? e.g. with code::blocks? If it's not a total nightmare then I'll give it a try...
Wow, you're expecting a modified version of mingw to produce trustworthy Windows binaries when you're not even running it on Windows..!? Good luck with that!
Well, I don't know whether this is just a hobby thing or whether you're planning on releasing these builds, but you're a braver man than I am if you're releasing exes that were built like that!
These are intended to be released, it's not a hobby.
I did manage to get JUCE compiled w/ my mingw-32 on Linux, and the exe tests fine and the executed programs even look exactly the same on Linux and Win32... which is rather the point.
The reason I am not using MSVC is twofold:
First, I am really, really keen on using the same toolset on all platforms, as far as possible. I've done a lot of work with the mingw toolchain, and found them quite reliable. So now I've got Linux, Windows 32-bit and Android all working just fine w/ gcc. There's some kind of problem w/ OS/X, which I've yet to figure out.
Second, I the build tools on Windows are (really) bad, and not conducive to batch building.
I guess a third reason is I'm not interested in paying MS for a properly supported version of MSVC...