Configuration for the mingw-w64 Cygwin packages in opam

The mingw-w64 ports of OCaml require access to GCC, the assembler and binutils. This set of packages performs two tasks. Firstly, it ensures that the directory containing the runtime DLLS are added to PATH. A typical Cygwin installation requires C:\cygwin64\usr\x86_64-w64-mingw32\sys-root\mingw\bin to be added to PATH, for example.

Secondly, for opam's internally managed Cygwin installation, they install shim executables to provide the cygpath utility along with all tool-prefixed programs from the -gcc-core, -gcc-g++ and -binutils packages from the mingw64-i686 and mingw64-x86_64 package sets.

In earlier versions of mingw-w64-shims, the mingw-w64-shims package formed part of this set. Installing mingw-w64-shims is no longer necessary.