Merge branch 'bc/use-sha256-by-default-in-3.0' into seen

Prepare to flip the default hash function to SHA-256.

* bc/use-sha256-by-default-in-3.0:
  Enable SHA-256 by default in breaking changes mode
  t5300: choose the built-in hash outside of a repo
  t4042: choose the built-in hash outside of a repo
  t1007: choose the built-in hash outside of a repo
  t: default to compile-time default hash if not set
  setup: use the default algorithm to initialize repo format
  Use original hash for legacy formats
  builtin: use default hash when outside a repository
  hash: add a constant for the original hash algorithm
  hash: add a constant for the default hash algorithm

diff --cc builtin/diff.c
Simple merge

diff --cc builtin/hash-object.c
Simple merge

diff --cc builtin/index-pack.c
Simple merge

diff --cc builtin/receive-pack.c
Simple merge

diff --cc builtin/shortlog.c
Simple merge

diff --cc bundle.c
Simple merge

diff --cc fetch-pack.c
Simple merge

diff --cc hash.h
Simple merge

diff --cc t/t1007-hash-object.sh
Simple merge

diff --cc t/t5300-pack-object.sh
Simple merge

diff --cc t/test-lib-functions.sh
Simple merge

diff --cc t/test-lib.sh
Simple merge