I've followed An_dz steps, which correctly match the steps at http://www.msys2.org/
, all works correctly.
Static builds are in no way mandatory. If you have a dll clash, that's the fault of your own system setup.
I've put STATIC as an option into config.template / Makefile to have a fully static build if one desires. It works just fine with SDL1 and SDL2 as well when one correctly uses the sdl1/2-config parameters.
Also works for makeobj. I note that on my system, if I don't build makeobj static, it finds another version of zlib1.dll somewhere on the path which is not compatable with the build. As long as I have the correct zlib1.dll in the same directory as the makeobj.exe, then it uses that. But, makeobj as a command line util should really always be built static so it can be distributed as a single .exe.
I guess you've also found errors like the missing .exe icon, and SDL1/2 versions missing MIDI were due to incompletely changing OSTYPE mingw to mingw64. Moot now that it's back, but mingw64 was a terrible name - too ambiguous. If there's still a desire to change from mingw, I suggest mingw-w64 if not an even more complete specifier.
I'll try again to make sure I've not forgotten anything.
I'd suggest also installing the 'svn' and 'patch' packages.
For completeness, maybe also a blurb on the svn checkout, and config.default setup.