[PATCH v2 0/5] COPYING: modernize, steal boilerplate from linux.git

This updates our COPYING file to be in line with linux.git's to clarify how the licenses of embedded sub-projects are handled. This doesn't change Git's license in any way (still GPL v2).

See the v1 for a longer summary: https://lore.kernel.org/git/cover-0.5-00000000000-20211002T091212Z-avarab@gmail.com/

This v2 fixes typos in 3/5, and clarifies why we need to use the specific "COPYING" data in the lib-diff.sh tests.

Ævar Arnfjörð Bjarmason (5):
  "lib-diff" tests: make "README" and "COPYING" test data smaller
  tests: stop using top-level "README" and "COPYING" files
  COPYING: remove mention of GPLv3, clarify sub-project COPYING
  COPYING: move GPL text to a "GPL-2.0" file
  GPL-2.0: update to byte-for-byte match the FSF's version

 COPYING                           | 377 ++----------------------------
 t/lib-diff/COPYING => GPL-2.0     |  60 ++---
 t/.gitattributes                  |   1 -
 t/lib-diff-data.sh                |  22 ++
 t/lib-diff.sh                     |   2 +
 t/lib-diff/README                 |  46 ----
 t/t4003-diff-rename-1.sh          |   4 +-
 t/t4005-diff-rename-2.sh          |   4 +-
 t/t4007-rename-3.sh               |   5 +-
 t/t4008-diff-break-rewrite.sh     |   4 +-
 t/t4009-diff-rename-4.sh          |   4 +-
 t/t4022-diff-rewrite.sh           |   6 +-
 t/t4023-diff-rename-typechange.sh |  11 +-
 t/t7001-mv.sh                     |   5 +-
 t/t7101-reset-empty-subdirs.sh    |  11 +-
 15 files changed, 89 insertions(+), 473 deletions(-)
 rename t/lib-diff/COPYING => GPL-2.0 (92%)
 create mode 100644 t/lib-diff-data.sh
 delete mode 100644 t/lib-diff/README

Range-diff against v1:
1:  8a4ca06bce0 ! 1:  f834cf74873 "lib-diff" tests: make "README" and "COPYING" test data smaller
    @@ Commit message
         "COPYING" as test data, or mock data that's dissimilar. Let's provide
         that with a "COPYING_test_data" function instead.
     
    +    We're not replacing this with some other generic test
    +    data (e.g. "lorum ipsum") because these tests require test file header
    +    to be the old "COPYING" file. See e.g. "t4003-diff-rename-1.sh" which
    +    changes the file, and then does full "test_cmp" comparisons on the
    +    resulting "git diff" output.
    +
         This change only changes tests that used the "lib-diff.sh" library,
         but splits up what they need into a new "lib-diff-data.sh". A
         subsequent commit will change related tests that were missed in
2:  f07025682e1 = 2:  f7cd2f31ccb tests: stop using top-level "README" and "COPYING" files
3:  e91f8ce6984 ! 3:  44375bece46 COPYING: remove mention of GPLv3, clarify sub-project COPYING
    @@ Commit message
     
         The COPYING file added in [1] is a product of its era, at the time
         discussions around the GPLv3 were quite active. Since then we have had
    -    almost on "GPL v2 or later" notices anywhere.
    +    almost no "GPL v2 or later" notices anywhere.
     
         Since then[2][3] linux.git has replaced its version of almost the
         identical wording with something that's a bit more formal, and which
    -    isn't mostly addressing a hypothetical future GPL v3 migratin. Let's
    +    isn't mostly addressing a hypothetical future GPL v3 migration. Let's
         do the same. Now we:
     
         A. Let it suffice to say that things are licensed under GPL v2 unless
4:  7804709f585 = 4:  ccb26274cc6 COPYING: move GPL text to a "GPL-2.0" file
5:  0545fd06cac = 5:  6fe2e601b13 GPL-2.0: update to byte-for-byte match the FSF's version