Steps for using Mingw-cross-env

1. Install the mingw-cross-env requirements: ​http://mingw-cross-env.nongnu.org/#requirements
2. Download mingw-cross-env:

   hg clone http://hg.savannah.nongnu.org/hgweb/mingw-cross-env
   

Note: The commands below use mingw-cross-env/ as the base directory where mingw-cross-env resides. Replace this with the path you actually use, e.g. /opt/mingw/.

Second note: The install step includes setting your PATH variable to include mingw-cross-env/usr/bin.

3. Build gcc and Warzone requirements (in mingw-cross-env/):

   make gcc JOBS=4 zlib bfd gettext jpeg libpng ogg vorbis openal theora qt sdl physfs glew freetype fontconfig fribidi libiberty
   

JOBS=X specifies how many processes to run concurrently, corresponding to -jX in normal make runs. -jX will build X packages in parallel, this is much less useful.

Add mingw-cross-env/usr/bin to the PATH, e.g.

export PATH=/opt/mingw/usr/bin:$PATH

5. Add some additionally needed files:

From ​http://download.gna.org/warzone/development/devpkg/2.3-cross/20100127-devpkg_tarbomb-2.3.tar.bz2

bin/dbghelp.dll.license.txt 
bin/dbghelp.dll
bin/oalinst.exe

lib/libdbghelp.a

include/dbghelp.h 

to mingw-cross-env/usr/i686-pc-mingw32/<dir>/<file>

From your Warzone clone:

pkg/nsis/fonts.conf.wd_*

and from your system:

/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf 
/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf

to mingw-cross-env/usr/i686-pc-mingw32/etc/fonts/

6. Execute autogen.sh then configure like so (in the build directory / warzone directory for in-tree builds):

   ./configure --host=i686-pc-mingw32 --enable-static PKG_CONFIG=i686-pc-mingw32-pkg-config \
           CC_FOR_BUILD="gcc" CXX_FOR_BUILD="g++" \
           CFLAGS="-pipe -m32 -march=i686 -O2 -g -gstabs -g3" \
           CXXFLAGS="-pipe -m32 -march=i686 -O2 -g -gstabs -g3 -fno-exceptions" \
           --enable-installer --with-installer-extdir="/mingw-cross-env-dir/usr/i686-pc-mingw32" \
           --with-installer-version="2.46.0.0" --disable-debug
   

And run

make

after.