Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] next goal: sdl2-ttf (user goal)
[__0] rejecting: sdl2-ttf-2.1.3 (conflict: pkg-config package SDL2_ttf==2.0.12
|| >2.0.12, not found in the pkg-config database)
[__0] rejecting: sdl2-ttf-2.1.2, sdl2-ttf-2.1.1, sdl2-ttf-2.1.0,
sdl2-ttf-2.0.2, sdl2-ttf-2.0.1, sdl2-ttf-2.0.0, sdl2-ttf-1.0.0,
sdl2-ttf-0.2.2, sdl2-ttf-0.2.1, sdl2-ttf-0.2.0 (constraint from user target
requires ==2.1.3)
[__0] fail (backjumping, conflict set: sdl2-ttf)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: sdl2-ttf