Merge branch 'ab/config-based-hooks-1'

Mostly preliminary clean-up in the hook API.

* ab/config-based-hooks-1:
  hook-list.h: add a generated list of hooks, like config-list.h
  hook.c users: use "hook_exists()" instead of "find_hook()"
  hook.c: add a hook_exists() wrapper and use it in bugreport.c
  hook.[ch]: move find_hook() from run-command.c to hook.c
  Makefile: remove an out-of-date comment
  Makefile: don't perform "mv $@+ $@" dance for $(GENERATED_H)
  Makefile: stop hardcoding {command,config}-list.h
  Makefile: mark "check" target as .PHONY

diff --cc Makefile
Simple merge

diff --cc builtin/am.c
Simple merge

diff --cc builtin/merge.c
Simple merge

diff --cc config.mak.uname
Simple merge

diff --cc refs.c
Simple merge

diff --cc sequencer.c
Simple merge