Patch from Rene Liebscher: this adds "--help-foo" options to list the
values that "--foo" can take for various commands: eg. what formats for
"sdist" and "bdist", what compilers for "build_ext" and "build_clib".

I have *not* reviewed this patch; I'm checking it in as-is because it also
fixes a paper-bag-over-head bug in bdist.py, and because I won't have
time to review it properly for several days: so someone else can
test it for me, instead!
diff --git a/Lib/distutils/command/bdist.py b/Lib/distutils/command/bdist.py
index 3cd1eb0..66ef113 100644
--- a/Lib/distutils/command/bdist.py
+++ b/Lib/distutils/command/bdist.py
@@ -21,8 +21,7 @@
     user_options = [('bdist-base=', 'b',
                      "temporary directory for creating built distributions"),
                     ('formats=', None,
-                     "formats for distribution " +
-                     "(gztar, bztar, zip, rpm, ... )"),
+                     "formats for distribution"),
                    ]
 
     # The following commands do not take a format option from bdist
@@ -33,12 +32,28 @@
     default_format = { 'posix': 'gztar',
                        'nt': 'zip', }
 
-    format_command = { 'gztar': 'bdist_dumb',
-                       'bztar': 'bdist_dumb',
-                       'ztar':  'bdist_dumb',
-                       'tar':   'bdist_dumb',
-                       'rpm':   'bdist_rpm',
-                       'zip':   'bdist_dumb', }
+    format_command = { 'gztar': ('bdist_dumb',"gzipped tar-file"),
+                       'bztar': ('bdist_dumb',"bzip2-ed tar-file"),
+                       'ztar':  ('bdist_dumb',"compressed tar-file"),
+                       'tar':   ('bdist_dumb',"tar-file"),
+                       'rpm':   ('bdist_rpm',"rpm distribution"),
+                       'zip':   ('bdist_dumb',"zip-file"),
+		        }
+
+    # prints all possible arguments to --format
+    def show_formats():
+	from distutils.fancy_getopt import FancyGetopt 
+	list_of_formats=[]
+	for format in bdist.format_command.keys():
+	    list_of_formats.append(("formats="+format,None,bdist.format_command[format][1]))
+	list_of_formats.sort()
+	pretty_printer=FancyGetopt(list_of_formats)
+	pretty_printer.print_help("List of available distribution formats:")
+
+    help_options = [
+        ('help-formats', None,
+         "lists available distribution formats",show_formats),
+	]
 
 
     def initialize_options (self):
@@ -74,14 +89,14 @@
         for format in self.formats:
 
             try:
-                cmd_name = self.format_command[self.format]
+                cmd_name = self.format_command[format][0]
             except KeyError:
                 raise DistutilsOptionError, \
-                      "invalid format '%s'" % self.format
+                      "invalid format '%s'" % format
 
             sub_cmd = self.reinitialize_command(cmd_name)
             if cmd_name not in self.no_format_option:
-                sub_cmd.format = self.format
+                sub_cmd.format = format
             self.run_command (cmd_name)
 
     # run()