Default folder for resources and css on macOS is really odd and no configure option available to set the right path

[barracuda156]

Why would anyone want to dump some random support files into ${prefix}/bin together with the binary? But this is where they are looked for, since apparently the build system ignores ABADDON_RESOURCE_DIR on macOS, and instead uses a relative .. So nothing gets found on the app launch.

The same will happen on any *BSD, since there is no macro for them, so “unknown OS” will be used, which is again ..

This is arguably a strange default, but at least, perhaps, let the user set the correct location?