[Mingw-cross-env-list] Building x86_64 binaries for Windows

[Franz Schrober]

Hi,

more and more users are requesting 64 bit versions of their programs (even when 
WOW64 exists). So I asked myself whether it is possible to compile a mingw-w64 
(please correct me when the name is wrong) cross compiling toolchain using MXE?

I found this bug 39 [1] which seems to allow this, but it is unmerged and the 
current state is unclear to me. Was it already possible to build a 64 bit 
toolchain and now it is only possible to build all toolchains at once? When 
yes, what must I do to compile a 64 bit toolchain from the current 
master/stable branch?

[1] https://github.com/mxe/mxe/issues/39