update for meson / r48

inih upstream now has a build system for system installation, so one can use that. As a result, I think you should drop your runtime patch (it's good idea though, consider doing something like this upstream), since a lot of projects will now just link against the upstream library, so we shouldn't do our own stuff in Debian. I regenerated the symbols file, beginning from 48 to highlight this. We can drop the tests. The tests are nice for upstream, but don't really have a use case for building the library, especially with the runtime patch dropped. I also changed the upstream name to inih, since upstream doesn't mention libinih anywhere, and removed the debian/.gitignore, you can just run debclean to remove all generated files. One more nice thing about the build file is that we can ship INIReader (aka C++ inih bindings) and don't need to care about generating pkg-config files.

WIP since 48 is not released yet.