Log Message:
goredo: update to 2.1.0. From the changelog:

* Mistakenly path to '.do' file was not absolute and OS can refuse to
  run it because it is not in '$PATH'.

* Huge quantity of performance optimisations.

* Fixed possible unexpected lock file closing.

* When resulting target has the same contents, it does not replace
  already existing one.  That was done previously.  But now it also
  copies the file's mode flags to the target (for example making it
  executable).

* If 'redo-*' command runs under control of another (top-level) redo,
  then it does not parse the flags as options and treat each argument
  as a target, allowing passing the targets with dashes in the
  beginning.

* Prevented possible concurrent stderr writing by multiple running
  targets.

* 'redo-depfix' command now always rewrites dependency files and
  calculates checksums of the files.

* Own binary format is used for dependency files ('.dep'), instead of
  recfile ('.rec') one.  It is several times smaller and much faster
  to parse.  You must run 'redo-depfix' to convert all existing
  '.redo/*.rec' files to that binary format.

* 'redo-dep2rec' command appeared, that can convert '.dep' to recfile
  on stdout.