anchor.diff: -{ go, govers, parallel, lib, fetchgit, fetchhg }:
  +{ go, govers, parallel, lib, fetchgit, fetchhg, rsync }:
   
   { name, buildInputs ? [], nativeBuildInputs ? [], passthru ? {}, preFixup ? ""
   
  
positive.code: 
  # Extra sources to include in the gopath
  , extraSrcs ? [ ]
  
  # go2nix dependency file
  , goDeps ? null
  
negative.code:     chmod -R u+w goPath/*
      mv goPath/* "go/src/${goPackagePath}"
      rmdir goPath
  
    '') + (lib.optionalString (extraSrcPaths != []) ''
      ${rsync}/bin/rsync -a ${lib.concatMapStrings (p: "${p}/src") extraSrcPaths} go
  
    '') + ''
      export GOPATH=$NIX_BUILD_TOP/go:$GOPATH
  