Get the latest OpenGL Registry.
wget https://cvs.khronos.org/svn/repos/ogl/trunk/doc/registry/public/api/gl.xml
Build and run the generator.
cabal configure -fgenerator
cabal build opengl-wrangler-gen
./dist/build/opengl-wrangler-gen/opengl-wrangler-gen
Build and install the library.
cabal build
cabal install