[PATCHv3 00/11] Expose the submodule parallelism to the user

Where does it apply? --- This series applies on top of d075d2604c0f92045caa8d5bb6ab86cf4921a4ae (Merge branch 'rs/daemon-plug-child-leak' into sb/submodule-parallel-update) and replaces the previous patches in sb/submodule-parallel-update

What does it do? --- This series should finish the on going efforts of parallelizing submodule network traffic. The patches contain tests for clone, fetch and submodule update to use the actual parallelism both via command line as well as a configured option. I decided to go with "submodule.jobs" for all three for now.

What's new in v3? ---

 * 3 new patches (make it compile in Windows, better warnings in posix environment
   for setting fds to non blocking, drop check against NULL)
 * adressed reviews by Eric for readability. :) 
 * addressed Junios comments for the new clone helper function

Stefan Beller (11):
  run_processes_parallel: delimit intermixed task output
  run-command: report failure for degraded output just once
  run-command: omit setting file descriptors to non blocking in Windows
  submodule-config: keep update strategy around
  submodule-config: drop check against NULL
  submodule-config: remove name_and_item_from_var
  submodule-config: introduce parse_generic_submodule_config
  fetching submodules: respect `submodule.jobs` config option
  git submodule update: have a dedicated helper for cloning
  submodule update: expose parallelism to the user
  clone: allow an explicit argument for parallel submodule clones

 Documentation/config.txt        |   7 ++
 Documentation/git-clone.txt     |   6 +-
 Documentation/git-submodule.txt |   7 +-
 builtin/clone.c                 |  19 +++-
 builtin/fetch.c                 |   2 +-
 builtin/submodule--helper.c     | 239 ++++++++++++++++++++++++++++++++++++++++
 git-submodule.sh                |  54 ++++-----
 run-command.c                   |  26 ++++-
 submodule-config.c              | 109 +++++++++++-------
 submodule-config.h              |   3 +
 submodule.c                     |   5 +
 t/t5526-fetch-submodules.sh     |  14 +++
 t/t7400-submodule-basic.sh      |   4 +-
 t/t7406-submodule-update.sh     |  27 +++++
 14 files changed, 433 insertions(+), 89 deletions(-)