Merge branch 'jc/commit-hook-authorship'

"git commit --author=$name" did not tell the name that was being recorded
in the resulting commit to hooks, even though it does do so when the end
user overrode the authorship via the "GIT_AUTHOR_NAME" environment
variable.

* jc/commit-hook-authorship:
  commit: pass author/committer info to hooks
  t7503: does pre-commit-hook learn authorship?
  ident.c: add split_ident_line() to parse formatted ident line

diff --cc builtin/commit.c
Simple merge

diff --cc cache.h
Simple merge