Python 2.7, PIP: "Failed building wheel for ..."
<p>First time using pip, trying to use <a href="https://github.com/GoogleCloudPlatform/python-docs-samples" rel="noreferrer">the python-docs-samples tutorial library</a>. When I run the "python -m pip install -r requirements.txt" command, a lot of scripts are pulled in, but then I get a series of "Failed building wheel" errors. One of these is shown in the attached code block (please pardon the hand-entered word-wrap linebreaks).</p>

<p>What is the problem? Anyone seen this before? I have not altered any parts of the library or the code that uses it, and I'm using Python 2.7.12 which is supposed to have good built-in support for PIP.</p>

<pre><code>  Running setup.py bdist_wheel for PyYAML ... error
  Complete output from command C:\users\owner\python-docs-samples\env\Scripts\python.exe 
-u -c "import setuptools, tokenize;__file__='c:\\users\\owner\\appdata\\local\\temp\\
pip-build-86ysrg\\PyYAML\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__)
.read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d c:\users\owner\appdata
\local\temp\tmpljy6z0pip-wheel- --python-tag cp27:
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build\lib.win32-2.7
  creating build\lib.win32-2.7\yaml
  copying lib\yaml\composer.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\constructor.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\cyaml.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\dumper.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\emitter.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\error.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\events.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\loader.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\nodes.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\parser.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\reader.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\representer.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\resolver.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\scanner.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\serializer.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\tokens.py -&gt; build\lib.win32-2.7\yaml
  copying lib\yaml\__init__.py -&gt; build\lib.win32-2.7\yaml
  running build_ext
  creating build\temp.win32-2.7
  creating build\temp.win32-2.7\Release
  checking if libyaml is compilable
  error: [Error 2] The system cannot find the file specified

  ----------------------------------------
  Failed building wheel for PyYAML
  Running setup.py clean for PyYAML
</code></pre>