Merge branch 'jk/git-prompt'

* jk/git-prompt:
  contrib: add credential helper for OS X Keychain
  Makefile: OS X has /dev/tty
  Makefile: linux has /dev/tty
  credential: use git_prompt instead of git_getpass
  prompt: use git_terminal_prompt
  add generic terminal prompt function
  refactor git_getpass into generic prompt function
  move git_getpass to its own source file
  imap-send: don't check return value of git_getpass
  imap-send: avoid buffer overflow

Conflicts:
	Makefile

cache.h

@@ -1028,7 +1028,6 @@ struct ref {
 extern struct ref *find_ref_by_name(const struct ref *list, const char *name);
 
 #define CONNECT_VERBOSE       (1u << 0)
-extern char *git_getpass(const char *prompt);
 extern struct child_process *git_connect(int fd[2], const char *url, const char *prog, int flags);
 extern int finish_connect(struct child_process *conn);
 extern int git_connection_is_socket(struct child_process *conn);