[PATCH v2 0/4] Makefile/coccicheck: fix bugs and speed it up

Addresses feedback on v1:

 - The removal of the "cat $@.log" is gone.
 - Split up into N changes.
 - Explained why 960154b9c17 (coccicheck: optionally batch spatch
   invocations, 2019-05-06) broke things and produced duplicate hunks
   in 2/4: tl;dr: spatch does its own locking etc., xargs -n trips it
   up.
 - Set number of batch processes to 8, as suggested by Jeff King.

Ævar Arnfjörð Bjarmason (4):
  Makefile/coccicheck: add comment heading for all SPATCH flags
  Makefile/coccicheck: speed up and fix bug with duplicate hunks
  Makefile/coccicheck: allow for setting xargs concurrency
  Makefile/coccicheck: set SPATCH_BATCH_SIZE to 8

 Makefile | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

Range-diff: 1: 3dfadacc255 < -: ----------- Makefile: fix bugs in coccicheck and speed it up -: ----------- > 1: b556c747afd Makefile/coccicheck: add comment heading for all SPATCH flags -: ----------- > 2: 031e3418491 Makefile/coccicheck: speed up and fix bug with duplicate hunks -: ----------- > 3: 88eab1af9a0 Makefile/coccicheck: allow for setting xargs concurrency -: ----------- > 4: 4b9679fcaba Makefile/coccicheck: set SPATCH_BATCH_SIZE to 8