I'm working on an Autools based build system but it is not finished jet. For now I have included configure.ac and Makefile.am for Autotools experts to have a look at. If you just want to compile the engine execute the following commands. This will give you a libsolidity.so shared library which you can copy to the gtk3 theming engines directory.

$ valac --pkg=gmodule-2.0 --pkg=gtk+-3.0 -C solidity.vala
$ gcc -shared -fPIC `pkg-config --cflags --libs glib-2.0 gmodule-2.0 gtk+-3.0` -o libsolidity.so solidity.c
