Resolving dependencies...
Starting     primitive-0.7.1.0
Starting     containers-0.6.2.1
Building     containers-0.6.2.1
Building     primitive-0.7.1.0
Completed    primitive-0.7.1.0
Starting     vector-0.12.1.2
Building     vector-0.12.1.2
Completed    containers-0.6.2.1
Starting     binary-0.8.8.0
Building     binary-0.8.8.0
Completed    vector-0.12.1.2
Completed    binary-0.8.8.0
Starting     text-1.2.4.0
Building     text-1.2.4.0
Completed    text-1.2.4.0
Starting     hashable-1.3.0.0
Building     hashable-1.3.0.0
Completed    hashable-1.3.0.0
Starting     alfred-margaret-1.0.0.0
Building     alfred-margaret-1.0.0.0
Failed to install alfred-margaret-1.0.0.0
Build log ( /home/builder/.cabal/logs/ghc-8.6.3/alfred-margaret-1.0.0.0-D8AhOVEMHtO7WyE30akPvS.log ):
cabal: Entering directory '/tmp/cabal-tmp-29871/alfred-margaret-1.0.0.0'
Configuring alfred-margaret-1.0.0.0...
Preprocessing library for alfred-margaret-1.0.0.0..
Building library for alfred-margaret-1.0.0.0..
[1 of 3] Compiling Data.Text.AhoCorasick.Automaton ( src/Data/Text/AhoCorasick/Automaton.hs, dist/build/Data/Text/AhoCorasick/Automaton.o )

<no location info>: error:
    Warning: Couldn't figure out LLVM version!
             Make sure you have installed LLVM 6.0
ghc: could not execute: opt
cabal: Leaving directory '/tmp/cabal-tmp-29871/alfred-margaret-1.0.0.0'
cabal: Error: some packages failed to install:
alfred-margaret-1.0.0.0-D8AhOVEMHtO7WyE30akPvS failed during the building
phase. The exception was:
ExitFailure 1