Resolving dependencies...
Error: cabal: Could not resolve dependencies:
[__0] next goal: erebos (user goal)
[__0] rejecting: erebos-0.1.0 (conflict: pkg-config package libpjproject>=2.9,
not found in the pkg-config database)
[__0] fail (backjumping, conflict set: erebos)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: erebos