Resolving dependencies...
cabal: Could not resolve dependencies:
trying: llvm-ffi-3.4.0 (dependency of llvm-tf-3.0.3.1.6)
trying: llvm-ffi-3.4.0:-buildtools
rejecting: llvm-ffi-3.4.0:+specificpkgconfig (conflict: requires pkg-config
package llvm-3.4==3.4, not found in the pkg-config database)
rejecting: llvm-ffi-3.4.0:-specificpkgconfig (conflict: requires pkg-config
package llvm==3.4, not found in the pkg-config database)
Dependency tree exhaustively searched.