Fix doctest failures in sage-4.1.alpha1

[boothby]

The following occur in sage-4.1.alpha1:

The following tests failed:

        sage -t -long devel/sage/doc/fr/tutorial/programming.rst # 1 doctests failed
        sage -t -long devel/sage/sage/misc/darwin_utilities.pyx # 3 doctests failed
----------------------------------------------------------------------

they're both really easy fixes.

[was]

The change to module_list.py is wrong. If you do that, then Sage won't build on OS X 10.4, and will waste time/space on non-OS X. It's critical to only build that module if we're on OS X >= 10.5, since it isn't implemented for any other platform. the other part of the patch is fine.

[was]

I think the right change is to make the doctests in darwin_utilities.pyx marked

# optional - osx

[mvngu]

This is fixed in Sage 4.3.2.alpha1:

[mvngu@mod sage-4.3.2.alpha1]$ ./sage -t -long devel/sage/doc/fr/tutorial/programming.rst
sage -t -long "devel/sage/doc/fr/tutorial/programming.rst"  
	 [4.7 s]
 
----------------------------------------------------------------------
All tests passed!
Total time for all tests: 4.7 seconds
[mvngu@mod sage-4.3.2.alpha1]$ ./sage -t -long devel/sage/sage/misc/darwin_utilities.pyx
sage -t -long "devel/sage/sage/misc/darwin_utilities.pyx"   
	 [4.0 s]
 
----------------------------------------------------------------------
All tests passed!
Total time for all tests: 4.0 seconds

I'm closing this ticket as fixed.