[PATCH] setup.py: fix C extension compilation issue with OS X 10.9 and Xcode 5.1

[Mads Kiilerich]

On 04/15/2014 11:33 PM, Kent Frazier wrote:
> # HG changeset patch
> # User Kent Frazier <kentfrazier at gmail.com>
> # Date 1397593632 14400
> #      Tue Apr 15 16:27:12 2014 -0400
> # Node ID 7e50af3ecb436f3dcd8f856e6d244d458675a62c
> # Parent  76f68595ff8e5616a79dd79e962a97cc9ba58713
> setup.py: fix C extension compilation issue with OS X 10.9 and Xcode 5.1

> +    # XCode 5.1 changes clang such that it now fails to compile if the
> +    # -mno-fused-madd flag is passed, but the version of Python shipped with
> +    # OS X 10.9 Mavericks includes this flag. This causes problems in all
> +    # C extension modules, and a bug has been filed upstream at
> +    # http://bugs.python.org/issue21244. We also need to patch this here
> +    # so Mercurial can continue to compile in the meantime.
> +    if xcode51:
> +        cflags = get_config_var('CFLAGS')
> +        if re.search(r'-mno-fused-madd\b', cflags) is not None:
> +            os.environ['CFLAGS'] = (
> +                os.environ.get('CFLAGS', '') + ' -Qunused-arguments')

Nice to have a workaround so it works out of the box - thanks.

The error message it avoids is:

clang: error: unknown argument: '-mno-fused-madd' 
[-Wunused-command-line-argument-hard-error-in-future]
clang: note: this will be a hard error (cannot be downgraded to a 
warning) in the future

Do you have any thoughts on the merits of -Qunused-arguments compared to 
the apparently more narrow 
-Wno-error=unused-command-line-argument-hard-error-in-future ?

/Mads