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/build.py b/Lib/distutils/command/build.py
index b0894b8..c064f83 100644
--- a/Lib/distutils/command/build.py
+++ b/Lib/distutils/command/build.py
@@ -9,6 +9,7 @@
 import sys, os
 from distutils.core import Command
 from distutils.util import get_platform
+from distutils.ccompiler import show_compilers
 
 class build (Command):
 
@@ -35,6 +36,10 @@
         ('force', 'f',
          "forcibly build everything (ignore file timestamps)"),
         ]
+    help_options = [
+        ('help-compiler', None,
+         "lists available compilers",show_compilers),
+	]
 
     def initialize_options (self):
         self.build_base = 'build'