Index: pkg_resources.py
===================================================================
--- pkg_resources.py	(revision 42250)
+++ pkg_resources.py	(working copy)
@@ -136,6 +136,19 @@
 def _macosx_arch(machine):
     return {'PowerPC':'ppc', 'Power_Macintosh':'ppc'}.get(machine,machine)
 
+def _get_max_platform(plat):
+    """Return this platform's maximum compatible version.
+
+    get_platform() reports the minimum version of Mac OS X
+    that would be required to use extensions produced by distutils.
+    To allow usage of packages that explicitly require a newer version
+    of Mac OS X, we must also know the current version of the OS.
+    """
+    m = macosVersionString.match(plat)
+    if m is not None:
+        plat = 'macosx-%s-%s' % (_macosx_version(), m.group(2))
+    return plat
+
 def get_platform():
     """Return this platform's string for platform-specific distributions
 
@@ -171,6 +184,9 @@
     """
     if provided is None or required is None or provided==required:
         return True     # easy case
+    provided = _get_max_platform(provided)
+    if provided==required:
+        return True     # the other easy case
 
     # Mac OS X special cases
     reqMac = macosVersionString.match(required)