Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] next goal: gtk-sni-tray (user goal)
[__0] rejecting: gtk-sni-tray-0.1.8.0 (conflict: pkg-config package
gtk+-3.0-any, not found in the pkg-config database)
[__0] rejecting: gtk-sni-tray-0.1.7.0, gtk-sni-tray-0.1.6.2,
gtk-sni-tray-0.1.6.0, gtk-sni-tray-0.1.5.0, gtk-sni-tray-0.1.4.0,
gtk-sni-tray-0.1.3.2, gtk-sni-tray-0.1.3.1, gtk-sni-tray-0.1.3.0,
gtk-sni-tray-0.1.2.1, gtk-sni-tray-0.1.2.0, gtk-sni-tray-0.1.1.0,
gtk-sni-tray-0.1.0.0 (constraint from user target requires ==0.1.8.0)
[__0] fail (backjumping, conflict set: gtk-sni-tray)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: gtk-sni-tray