Fix an issue with the detection of a non-existing SDK on OSX. Without this patch it wasn't possible after all to compile extensions on OSX 10.6 with the binary installer unless the user had installed the (non-default) 10.4u SDK.
Fix an issue with the detection of a non-existing SDK
on OSX. Without this patch it wasn't possible after all
to compile extensions on OSX 10.6 with the binary
installer unless the user had installed the (non-default)
10.4u SDK.

pypa/setuptools,pypa/setuptools,pypa/setuptools