What's the most sensible way to build and use 32/64-bit libraries with MSYS on Windows? Specifically, I am wondering about zlib and libpng along with SDL2.

I know there are pre-built versions available, but I am inevitably going to need to build other libraries in future.

I'm expecting things to go into /usr/local (which they do), but I'd like to have separate builds for 32-bit and 64-bit. I know I can put things into "lib32" or "lib64" using ./configure options pretty easily, but DLLs (e.g. SDL) seem to end up in "bin" so I assume I should create a "bin32" and "bin64" for those?

Then there's the issue of e.g. libpng not being able to find zlib's headers when using its MSYS makefile... Should I be editing these makefiles? It looks as though I should (things are commented-out etc.) but when I want to update to a newer version, I'll need to modify the makefile again.

It probably sounds like a really silly set of questions but I've always found that building and installing libraries on Windows feels really clumsy and I just want to make sure I'm not making a really messy dev environment.