Update: 10.9.3 resolves the issue with system CPython.
This is caused by the latest clang update from Apple that came with
Xcode 5.1 today and is affecting many, many people, so hopefully a fix will
Update: Did not expect this to get so much attention, but here's more
detail: the clang 3.4 Apple is shipping defaults to erroring on unknown
flags, but CPython builds modules using the same set of flags it was
compiled with originally. The system CPython was compiled with several
flags that are unknown by clang, thus causing this problem. The following
are the current Mavericks (10.9.2) CPython compile flags:
-fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os
-pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd
-DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes
-Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes
To resolve this issue you have a few options:
to your compile flags.
- Strip the unsupported flags from the sysconfigdata.py (as is noted in
- Compile a new python using homebrew.
- Wait for the next OS X update, which is rumored to include recompiled
Python/Ruby to remove this issue for system runtimes.