Using Python 3.2.2 and Python 3.3.0a2 (installed via 64-bit installers in official DMGs on python.org), 'distutils.util.get_platform()' returns an incorrect OS version when running on Mac OSX 10.7.

Using Python 2.6.7, and Python 2.7.1 (the versions included with Mac OSX), the output indicates 'macosx-10.7' correctly.

> for version in 2.6 2.7 3.2 3.3; do python${version} -c "from __future__ import print_function;import distutils.util,sys;print(sys.version.split()[0],distutils.util.get_platform())"; done 2.6.7 macosx-10.7-intel
2.7.1 macosx-10.7-intel
3.2.2 macosx-10.6-intel
3.3.0a2 macosx-10.6-intel

Some packages make use of this in their setup.py to determine the proper location of libraries.

For example, the 'readline' distribution's setup.py does so here: https://github.com/ludwigschwardt/python-readline/blob/6f0e801fa1632fcbb0e005eb9709aaa6051a0f28/setup.py#L33

It fails due to the incorrect assumption that it's running on 10.6 instead of 10.7.  Excerpt from "python setup.py bdist_egg":

building 'readline' extension
Compiling with an SDK that doesn't seem to exist: /Developer/SDKs/MacOSX10.6.sdk
Please check your Xcode installation
gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -DNDEBUG -g -O3 -isysroot /Developer/SDKs/MacOSX10.6.sdk -DHAVE_RL_CALLBACK -DHAVE_RL_CATCH_SIGNAL -DHAVE_RL_COMPLETION_APPEND_CHARACTER -DHAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK -DHAVE_RL_COMPLETION_MATCHES -DHAVE_RL_COMPLETION_SUPPRESS_APPEND -DHAVE_RL_PRE_INPUT_HOOK -I. -I/Library/Frameworks/Python.framework/Versions/3.2/include/python3.2m -c Modules/3.x/readline.c -o build/temp.macosx-10.6-intel-3.2/Modules/3.x/readline.o -Wno-strict-prototypes -isysroot /Developer/SDKs/MacOSX10.6.sdk -arch i386 -arch x86_64
In file included from Modules/3.x/readline.c:8:
/Library/Frameworks/Python.framework/Versions/3.2/include/python3.2m/Python.h:11:20: error: limits.h: No such file or directory