Change build system to autotools

[ftyers]

To fit in with the rest of the Apertium ecosystem.

[TinoDidriksen]

I would vastly prefer turning all the C++ packages to CMake, to make it easier work with IDEs and debuggers and to build on Windows with VC++ and vcpkg. autotools is just horrendous to work with cross-platform.

[ftyers]

I find CMake pretty horrendous to work with and prefer the build systems to be uniform across the project. You already work with apertium, lttoolbox, separable and lex-tools with autotools, let alone all of the language packages. If you want to work with CMake you can always maintain a branch cmake-build. This is the only non-autotools package, and it's only not autotools because you didn't follow the conventions.

[TinoDidriksen]

a3964ec