Merge branch 'pt/pull-builtin'

Reimplement 'git pull' in C.

* pt/pull-builtin:
  pull: remove redirection to git-pull.sh
  pull --rebase: error on no merge candidate cases
  pull --rebase: exit early when the working directory is dirty
  pull: configure --rebase via branch.<name>.rebase or pull.rebase
  pull: teach git pull about --rebase
  pull: set reflog message
  pull: implement pulling into an unborn branch
  pull: fast-forward working tree if head is updated
  pull: check if in unresolved merge state
  pull: support pull.ff config
  pull: error on no merge candidates
  pull: pass git-fetch's options to git-fetch
  pull: pass git-merge's options to git-merge
  pull: pass verbosity, --progress flags to fetch and merge
  pull: implement fetch + merge
  pull: implement skeletal builtin pull
  argv-array: implement argv_array_pushv()
  parse-options-cb: implement parse_opt_passthru_argv()
  parse-options-cb: implement parse_opt_passthru()

Documentation/technical/api-parse-options.txt

@@ -218,6 +218,19 @@ There are some macros to easily define options:
 	Use it to hide deprecated options that are still to be recognized
 	and ignored silently.
 
+`OPT_PASSTHRU(short, long, &char_var, arg_str, description, flags)`::
+	Introduce an option that will be reconstructed into a char* string,
+	which must be initialized to NULL. This is useful when you need to
+	pass the command-line option to another command. Any previous value
+	will be overwritten, so this should only be used for options where
+	the last one specified on the command line wins.
+
+`OPT_PASSTHRU_ARGV(short, long, &argv_array_var, arg_str, description, flags)`::
+	Introduce an option where all instances of it on the command-line will
+	be reconstructed into an argv_array. This is useful when you need to
+	pass the command-line option, which can be specified multiple times,
+	to another command.
+
 
 The last element of the array must be `OPT_END()`.