I have just updated the mingw-w64 cross compilers Cygwin 32bit and
64bit to mingw64-*-gcc-5.4.0-2.

Unlike the Cygwin gcc, this version DOES NOT PRESERVER C++ ABI from
gcc4. Please rebuild all your C++ libraries.

==== PLEASE RECOMPILE ALL YOUR C++ CODE FOR ABI COMPATIBILITY ====

The cross compiler can produce Win32 and Win64 native binaries. As a
cross compiler, you may use --host=i686-w64-mingw32 or
--host=x86_64-w64-mingw32 for autotools based source packages to build
for Windows.

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