These are instructions on building a Windows installer under Cygwin but with a MinGW toolchain and libraries.
The result is an installer which does not depend on Cygwin.
If you are looking for instructions on cross-compiling from linux or other systems, then refer to section above.

These instructions were written based on cygwin64.
When you install cygwin64 on your system, you will need to ensure that you have installed:

In addition, you will need the MinGW cross compilation packages.
At the time of writing this, the the list of packages installed which have been shown to work is contained in:
    win32/mingw_required_pkgs
That list was obtained via:
    cygcheck -c | grep mingw
In addition I have:
w32api-headers                        4.0.4-1                      OK
w32api-runtime                        4.0.4-1                      OK

Once these have all been installed then when building from a tarball, extract, cd win32 and run;
    ./build_pcb
This will create a windows installer.

If you are building from git you will need additional tools to build the documentation which can be skipped using:
    ./build_pcb --disable-doc