Issue:
Installing wesnoth on a fresh system (Solus 4.0 Budgie) creates a menu entry that silently fails to launch.

Steps to Reproduce:

1. Install wesnoth when sdl2-image, sdl2-mixer and sdl2-ttf are not installed.
2. Attempt to launch "Battle for Wesnoth" by clicking the icon or menu entry in the desktop environment.

Troubleshooting:
Running wesnoth in a terminal emulator returns the first applicable output below (in alphabetical order) and exits.

wesnoth: error while loading shared libraries: libSDL2_image-2.0.so.0: cannot open shared object file: No such file or directory
wesnoth: error while loading shared libraries: libSDL2_mixer-2.0.so.0: cannot open shared object file: No such file or directory
wesnoth: error while loading shared libraries: libSDL2_ttf-2.0.so.0: cannot open shared object file: No such file or directory

Diagnosis:
eopkg doesn't know that wesnoth requires sdl2-image, sdl2-mixer and sdl2-ttf.

$ eopkg info wesnoth | grep Dependencies
Dependencies        :
Reverse Dependencies:
Dependencies        :
Reverse Dependencies: wesnoth-dbginfo

Proposed Solution:
Add sdl2-image, sdl2-mixer and sdl2-ttf as runtime dependencies for wesnoth.