Resolving dependencies...
Configuring old-locale-1.0.0.7...
Building old-locale-1.0.0.7...
Installed old-locale-1.0.0.7
Downloading timestamper-1.0.1...
Configuring timestamper-1.0.1...
Building timestamper-1.0.1...
Failed to install timestamper-1.0.1
Build log ( /home/builder/.cabal/logs/timestamper-1.0.1.log ):
cabal: Entering directory '/tmp/cabal-tmp-18085/timestamper-1.0.1'
Configuring timestamper-1.0.1...
Building timestamper-1.0.1...
Preprocessing executable 'timestamper' for timestamper-1.0.1...
[1 of 1] Compiling Main             ( Main.lhs, dist/build/timestamper/timestamper-tmp/Main.o )

Main.lhs:18:42: error:
    Ambiguous occurrence ‘defaultTimeLocale’
    It could refer to either ‘Data.Time.Format.defaultTimeLocale’,
                             imported from ‘Data.Time.Format’ at Main.lhs:2:3-25
                             (and originally defined in ‘time-1.6.0.1:Data.Time.Format.Locale’)
                          or ‘System.Locale.defaultTimeLocale’,
                             imported from ‘System.Locale’ at Main.lhs:4:3-22
cabal: Leaving directory '/tmp/cabal-tmp-18085/timestamper-1.0.1'
cabal: Error: some packages failed to install:
timestamper-1.0.1 failed during the building phase. The exception was:
ExitFailure 1