Resolving dependencies... Starting hgmp-0.1.1 Starting long-double-0.1 Starting reflection-2.1.6 Building hgmp-0.1.1 Building long-double-0.1 Building reflection-2.1.6 Completed long-double-0.1 Completed reflection-2.1.6 Completed hgmp-0.1.1 Starting rounded-0.3 Failed to install rounded-0.3 Build log ( /home/builder/.cabal/logs/ghc-8.6.3/rounded-0.3-BjlQu7bPFhyD6UzsM5vnaM.log ): cabal: Entering directory '/tmp/cabal-tmp-20599/rounded-0.3' Configuring rounded-0.3... cabal: Missing dependency on a foreign library: * Missing (or bad) C library: mpfr This problem can usually be solved by installing the system package that provides this library (you may need the "-dev" version). If the library is already installed but in a non-standard location then you can use the flags --extra-include-dirs= and --extra-lib-dirs= to specify where it is.If the library file does exist, it may contain errors that are caught by the C compiler at the preprocessing stage. In this case you can re-run configure with the verbosity flag -v3 to see the error messages. cabal: Leaving directory '/tmp/cabal-tmp-20599/rounded-0.3' cabal: Error: some packages failed to install: rounded-0.3-BjlQu7bPFhyD6UzsM5vnaM failed during the configure step. The exception was: ExitFailure 1