Merge branch 'jn/help-everywhere'

* jn/help-everywhere: (23 commits)
  diff --no-index: make the usage string less scary
  merge-{recursive,subtree}: use usagef() to print usage
  Introduce usagef() that takes a printf-style format
  Let 'git <command> -h' show usage without a git dir
  Show usage string for 'git http-push -h'
  Let 'git http-fetch -h' show usage outside any git repository
  Show usage string for 'git stripspace -h'
  Show usage string for 'git unpack-file -h'
  Show usage string for 'git show-index -h'
  Show usage string for 'git rev-parse -h'
  Show usage string for 'git merge-one-file -h'
  Show usage string for 'git mailsplit -h'
  Show usage string for 'git imap-send -h'
  Show usage string for 'git get-tar-commit-id -h'
  Show usage string for 'git fast-import -h'
  Show usage string for 'git check-ref-format -h'
  http-fetch: add missing initialization of argv0_path
  Show usage string for 'git show-ref -h'
  Show usage string for 'git merge-ours -h'
  Show usage string for 'git commit-tree -h'
  ...

Conflicts:
	imap-send.c

diff --cc Makefile
Simple merge

diff --cc builtin-log.c
Simple merge

diff --cc builtin-rev-parse.c
Simple merge

diff --cc contrib/examples/builtin-fetch--tool.c
Simple merge

diff --cc imap-send.c
index 6c9938a0757a3c3b440c227951462f6972923afe,04e537406e4113d5c1ead7b7e4a1a425c9b2bf09..834301cf409c311d47b22a0f7504917a32847647
--- 1/imap-send.c
--- 2/imap-send.c
+++ b/imap-send.c
@@@ -94,7 -93,8 +94,9 @@@ struct msg_data 
        unsigned int crlf:1;
  };
  
+ static const char imap_send_usage[] = "git imap-send < <mbox>";
+ 
 +#undef DRV_OK
  #define DRV_OK          0
  #define DRV_MSG_BAD     -1
  #define DRV_BOX_BAD     -2
@@@ -1370,6 -1493,12 +1372,9 @@@ int main(int argc, char **argv
  
        git_extract_argv0_path(argv[0]);
  
 -      /* init the random number generator */
 -      arc4_init();
 -
+       if (argc != 1)
+               usage(imap_send_usage);
+ 
        setup_git_directory_gently(&nongit_ok);
        git_config(git_imap_config, NULL);