Merge branch 'master' into next

Merge branch 'master' into next

* master:
  pull: do not display fetch usage on --help-all
  git-tag.txt: list all modes in the description
  commit,status: describe -u likewise
  add: describe --patch like checkout, reset
  commit,merge,tag: describe -m likewise
  clone,init: describe --template using the same wording
  commit,status: describe --porcelain just like push
  commit,tag: use same wording for -F
  Revert "unpack_trees(): skip trees that are the same in all input"
  configure: use AC_LANG_PROGRAM consistently
  string_list_append: always set util pointer to NULL
  correct type of EMPTY_TREE_SHA1_BIN
  Obey p4 views when using client spec
  gitignore: add test-mktemp to ignore list
  repo-config: add deprecation warning