title: pyconfig.h - Cannot open include file: 'io.h': No such file or directory
body: <h3>Background:</h3>
  
  <ul>
  <li><p>I am new to python/Cpp and I am trying to install a python package python-crfsuite which needs to VS to compile.</p></li>
  <li><p>I have installed Anaconda3, pyhon3.6 all in VS2017 community installer (because I think it is better because I will use compiler of VS: <code>cl.exe</code>)</p></li>
  <li><p>I have already run <code>vcvarsall.bat</code></p></li>
  <li><p>All commands I run are in admin </p></li>
  </ul>
  
  <h3>Process:</h3>
  
  <p>When I trying to <code>pip install</code> python-crfsuite, it gives me the error:</p>
  
  <p><code>
   C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.10.25017\bin\HostX86\x86\cl.exe /c /nologo /Ox /W3 /GL /DNDEBUG /MD -Icrfsuite/include/ -Icrfsuite/lib/cqdb/include -Iliblbfgs/include -Ipycrfsuite -Icrfsuite/win32 -Iinclude "-IC:\Program Files\Anaconda3\include" "-IC:\Program Files\Anaconda3\include" /EHsc /Tppycrfsuite/_pycrfsuite.cpp /Fobuild\temp.win-amd64-3.6\Release\pycrfsuite/_pycrfsuite.obj
      _pycrfsuite.cpp
      c:\program files\anaconda3\include\pyconfig.h(59): fatal error C1083: Cannot open include file: 'io.h': No such file or directory
      error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community\\VC\\Tools\\MSVC\\14.10.25017\\bin\\HostX86\\x86\\cl.exe' failed with exit status 2
  </code></p>
  
  <ul>
  <li><p>I have read the answer from <a href="https://stackoverflow.com/questions/40018405/cython-cannot-open-include-file-io-h-no-such-file-or-directory">here</a>. So I try to replace the path in my system environment as following:
  <code>
  C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC 
  C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Tools\MSVC\14.10.25017\bin\HostX86\x86
  </code>
  =>
  <code>
  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC
  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.10.25017\bin\HostX86\x86
  </code>
  but it doesnt do anything for me.</p></li>
  <li><p>Then I try to download <code>io.h</code> and place in <code>C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.10.25017\include</code> but it is useless.</p></li>
  <li><p>Finally I try to use conda install <code>conda install -c conda-forge python-crfsuite</code> and it is <strong>success</strong></p></li>
  </ul>
  
  <h3>Question</h3>
  
  <ul>
  <li><p>Why <code>conda install</code> dose not have the problem with <code>io.h</code>, any difference with <code>pip install</code> ? </p></li>
  <li><p>Why there are multiple <code>cl.exe</code> in different path in VS (I am not so familiar with) and are there any difference in using different <code>cl.exe</code>?</p></li>
  </ul>
  
  <p>I ask these question because even if I installed Anaconda, if I want to use pip install, I have to face these problems and I still cannot figure it out</p>