clang：错误：未知参数：'-mno-fused-madd' [-Wunused-command-line-argument-hard-error-in-future]

Question

我在Mavericks操作系统上安装Scrapy时遇到了以下错误。

我已经安装了命令行工具和X11，但我不太清楚发生了什么，也没有在网上找到相同的错误。我觉得这可能和Xcode 5.1的一些变化有关。

谢谢大家的回答！

这是命令输出的一部分：

$pip install scrapy

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Downloading/unpacking cryptography>=0.2.1 (from pyOpenSSL->scrapy)
  Downloading cryptography-0.3.tar.gz (208kB): 208kB downloaded
  Running setup.py egg_info for package cryptography
    OS/X: confusion between 'cc' versus 'gcc' (see issue 123)
    will not use '__thread' in the C code
    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
    Traceback (most recent call last):
      File "<string>", line 16, in <module>
      File "/Users/agonzamart/.virtualenvs/Parser/build/cryptography/setup.py", line 156, in <module>
        "test": PyTest,
      File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/core.py", line 112, in setup
        _setup_distribution = dist = klass(attrs)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/dist.py", line 265, in __init__
        self.fetch_build_eggs(attrs.pop('setup_requires'))
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/dist.py", line 289, in fetch_build_eggs
        parse_requirements(requires), installer=self.fetch_build_egg
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/pkg_resources.py", line 618, in resolve
        dist = best[req.key] = env.best_match(req, self, installer)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/pkg_resources.py", line 862, in best_match
        return self.obtain(req, installer) # try and download/install
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/pkg_resources.py", line 874, in obtain
        return installer(requirement)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/dist.py", line 339, in fetch_build_egg
        return cmd.easy_install(req)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 623, in easy_install
        return self.install_item(spec, dist.location, tmpdir, deps)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 653, in install_item
        dists = self.install_eggs(spec, download, tmpdir)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 849, in install_eggs
        return self.build_and_install(setup_script, setup_base)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 1130, in build_and_install
        self.run_setup(setup_script, setup_base, args)
      File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 1118, in run_setup
        raise DistutilsError("Setup script exited with %s" % (v.args[0],))
    distutils.errors.DistutilsError: Setup script exited with error: command 'cc' failed with exit status 1
    Complete output from command python setup.py egg_info:
    OS/X: confusion between 'cc' versus 'gcc' (see issue 123)

will not use '__thread' in the C code

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

Traceback (most recent call last):

  File "<string>", line 16, in <module>

  File "/Users/agonzamart/.virtualenvs/Parser/build/cryptography/setup.py", line 156, in <module>

    "test": PyTest,

  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/core.py", line 112, in setup

    _setup_distribution = dist = klass(attrs)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/dist.py", line 265, in __init__

    self.fetch_build_eggs(attrs.pop('setup_requires'))

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/dist.py", line 289, in fetch_build_eggs

    parse_requirements(requires), installer=self.fetch_build_egg

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/pkg_resources.py", line 618, in resolve

    dist = best[req.key] = env.best_match(req, self, installer)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/pkg_resources.py", line 862, in best_match

    return self.obtain(req, installer) # try and download/install

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/pkg_resources.py", line 874, in obtain

    return installer(requirement)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/dist.py", line 339, in fetch_build_egg

    return cmd.easy_install(req)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 623, in easy_install

    return self.install_item(spec, dist.location, tmpdir, deps)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 653, in install_item

    dists = self.install_eggs(spec, download, tmpdir)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 849, in install_eggs

    return self.build_and_install(setup_script, setup_base)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 1130, in build_and_install

    self.run_setup(setup_script, setup_base, args)

  File "/Users/agonzamart/.virtualenvs/Parser/lib/python2.7/site-packages/setuptools/command/easy_install.py", line 1118, in run_setup

    raise DistutilsError("Setup script exited with %s" % (v.args[0],))

distutils.errors.DistutilsError: Setup script exited with error: command 'cc' failed with exit status 1

----------------------------------------
Cleaning up...
Command python setup.py egg_info failed with error code 1 in /Users/agonzamart/.virtualenvs/Parser/build/cryptography

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Answer 1

最新版本的clang把以前的警告提升到了错误级别。这意味着原本只是提醒你的问题，现在变得更严重了，直接影响到你的代码运行。如果你想恢复到以前的状态，可以在运行安装命令之前直接去掉这个行为：

ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future pip install <your package>

这样做应该可以解决问题，但如果出现什么意外情况，这里还有更多信息可以参考：clang错误：未知参数：'-mno-fused-madd'（Python包安装失败）

Answer 2

这个问题是因为在 Xcode 5.1 中，clang 的默认设置发生了变化，而苹果没有注意到这会导致使用系统 Python 的扩展模块构建失败。一个解决办法是先定义以下环境变量：

export CFLAGS=-Qunused-arguments
export CPPFLAGS=-Qunused-arguments

更新 [2014-05-16]：果然，苹果已经在 OS X 10.9.3 中修复了这个问题，更新了系统 Python（2.7、2.6 和 2.5），所以在使用最新的 Mavericks 和 Xcode 5.1+ 时，不再需要这个解决办法。不过，目前在 OS X 10.8.x（山狮，当前版本是 10.8.5）中，如果你在那儿使用 Xcode 5.1+，仍然需要这个解决办法。