anchor.diff:      (optionalString enableHsc2hsViaAsm "--hsc2hs-option=--via-asm")
     ];
   
  +  parallelBuildingFlags = "-j$NIX_BUILD_CORES" + optionalString stdenv.isLinux " +RTS -A64M -RTS";
  +
     crossCabalFlagsString =
       stdenv.lib.optionalString isCross (" " + stdenv.lib.concatStringsSep " " crossCabalFlags);
   
  
positive.code: , isExecutable ? false, isLibrary ? !isExecutable
  , jailbreak ? false
  , license
  # We cannot enable -j<n> parallelism for libraries because GHC is far more
  # likely to generate a non-determistic library ID in that case. Further
  # details are at <https://github.com/peti/ghc-library-id-bug>.
  #
  # Currently disabled for aarch64. See https://ghc.haskell.org/trac/ghc/ticket/15449.
  , enableParallelBuilding ? ((stdenv.lib.versionOlder "7.8" ghc.version && !isLibrary) || stdenv.lib.versionOlder "8.0.1" ghc.version) && !(stdenv.buildPlatform.isAarch64)
  , maintainers ? []
  , doCoverage ? false
  , doHaddock ? !(ghc.isHaLVM or false)
  
negative.code:   # same package in the (recursive) dependencies of the package being
    # built. Will delay failures, if any, to compile time.
    allowInconsistentDependencies ? false
  , maxBuildCores ? 16 # more cores usually don't improve performance: https://ghc.haskell.org/trac/ghc/ticket/9221
  , # If set to true, this builds a pre-linked .o file for this Haskell library.
    # This can make it slightly faster to load this library into GHCi, but takes
    # extra disk space and compile time.
  