Fixes the evaluation of packages in pkgs/os-specific/windows that
weren't updated to include a new lib parameter after the refactor from
stdenv.lib -> lib (#109490).
I originally only intended this change to fix
`pkgsCross.mingw32.buildPackages.gcc` & `pkgsCross.mingwW64.buildPackages.gcc`
to support building wine with `mingwSupport`, but I noticed this was
an issue for all updated windows packages. Most of these other
packages fail to build for other reasons.
Certain tools, e.g. compilers, are customarily prefixed with the name of
their target platform so that multiple builds can be used at once
without clobbering each other on the PATH. I was using identifiers named
`prefix` for this purpose, but that conflicts with the standard use of
`prefix` to mean the directory where something is installed. To avoid
conflict and confusion, I renamed those to `targetPrefix`.
This is for consistency with terminology in stdenv (and the terms
"hostDrv" and "buildDrv" are not very intuitive, even if they're
consistent with GNU terminology).
