It looks as though this change might have broken the compile on OS X. On my OS X 10.9 machine, building from a clean Git checkout of the master branch fails; the tail of the failed build looks like this:

./python.exe -E -S -m sysconfig --generate-posix-vars ;\
	if test $? -ne 0 ; then \
		echo "generate-posix-vars failed" ; \
		rm -f ./pybuilddir.txt ; \
		exit 1 ; \
	fi
Fatal Python error: Py_Initialize: unable to load the file system codec
Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 962, in _find_and_load
  File "<frozen importlib._bootstrap>", line 951, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 656, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 668, in exec_module
  File "<frozen importlib._bootstrap_external>", line 782, in get_code
  File "<frozen importlib._bootstrap_external>", line 842, in _cache_bytecode
  File "<frozen importlib._bootstrap_external>", line 867, in set_data
  File "<frozen importlib._bootstrap_external>", line 117, in _write_atomic
ValueError: negative file descriptor
/bin/sh: line 1: 35829 Abort trap: 6           ./python.exe -E -S -m sysconfig --generate-posix-vars
generate-posix-vars failed
make: *** [pybuilddir.txt] Error 1

Full build output attached.