CROSS-COMPILING FOR WINDOWS

Based on http://eigenclass.org/hiki.rb?cross+compiling+rcovrt


*) Install the MinGW cross-compiler

    Debian: apt-get install mingw32 mingw32-binutils mingw32-runtime

*) Download & extract a ruby distribution archive

*) Double the backslashes in the ALT_SEPARATOR definition in Makefile.in

*) Build & install it:

    env ac_cv_func_getpgrp_void=no \
       ac_cv_func_setpgrp_void=yes \
       rb_cv_negative_time_t=no \
       ac_cv_func_memcmp_working=yes \
       rb_cv_binary_elf=no \
       ./configure \
       --host=i586-mingw32msvc \
       --target=i386-mingw32 \
       --build=i686-linux \
       --prefix=~/ruby-mingw32

    make ruby

    make install

*) Build the extension (rake will build spidermonkey for you)

    # Remove any native binaries that are already built
    rake clean

    rake build CROSS=MINGW32 CROSSLIB=~/ruby-mingw32/lib/ruby/1.8/i386-mingw32