contrib/gcc-changelog: Add/improve --help

contrib/ChangeLog:

	* gcc-changelog/git_check_commit.py (__Main__): State in --help
	the default value for 'revisions'.
	* gcc-changelog/git_email.py (show_help): Add.
	(__main__): Handle -h and --help.

contrib/gcc-changelog/git_check_commit.py

@@ -23,7 +23,8 @@ from git_repository import parse_git_revisions
 parser = argparse.ArgumentParser(description='Check git ChangeLog format '
                                  'of a commit')
 parser.add_argument('revisions', default='HEAD', nargs='?',
-                    help='Git revisions (e.g. hash~5..hash or just hash)')
+                    help='Git revisions (e.g. hash~5..hash or just hash) - '
+                    'if not specified: HEAD')
 parser.add_argument('-g', '--git-path', default='.',
                     help='Path to git repository')
 parser.add_argument('-p', '--print-changelog', action='store_true',

contrib/gcc-changelog/git_email.py

@@ -72,10 +72,25 @@ class GitEmail(GitCommit):
                          commit_to_info_hook=lambda x: None)
 
 
-# With zero arguments, process every patch file in the ./patches directory.
-# With one argument, process the named patch file.
-# Patch files must be in 'git format-patch' format.
+def show_help():
+    print("""
+usage: git_email.py [--help] [patch file ...]
+
+Check git ChangeLog format of a patch
+
+With zero arguments, process every patch file in the
+./patches directory.
+With one argument, process the named patch file.
+
+Patch files must be in 'git format-patch' format.
+""")
+    sys.exit(0)
+
+
 if __name__ == '__main__':
+    if len(sys.argv) == 2 and (sys.argv[1] == '-h' or sys.argv[1] == '--help'):
+        show_help()
+
     if len(sys.argv) == 1:
         allfiles = []
         for root, _dirs, files in os.walk('patches'):