title: npm install that requires node-gyp fails on Windows
body: <p>I have a NPM project that uses <code>bufferutils</code> and <code>utf-8-validate</code>, both requiring node-gyp to install them. When I do <code>npm install</code>, I get following error:</p>
  
  <pre><code>&gt; bufferutil@1.2.1 install C:\Users\Marek\WEB\moje-skoly\web-app\node_modules\bufferutil                       
  &gt; node-gyp rebuild                                                                                             
  
  
  C:\Users\Marek\WEB\moje-skoly\web-app\node_modules\bufferutil {git}{hg}                                        
  {lamb} if not defined npm_config_node_gyp (node "C:\Users\Marek\AppData\Roaming\npm\node_modules\npm\bin\node-g
  yp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node "" rebuild )                        
  Building the projects in this solution one at a time. To enable parallel build, please add the "/m" switch.    
    bufferutil.cc                                                                                                
  C:\Users\Marek\.node-gyp\5.1.1\include\node\v8.h(18): fatal error C1083: Cannot open include file: 'stddef.h': 
   No such file or directory [C:\Users\Marek\WEB\moje-skoly\web-app\node_modules\bufferutil\build\bufferutil.vcx 
  proj]                                                                                                          
  gyp ERR! build error                                                                                           
  gyp ERR! stack Error: `C:\Program Files (x86)\MSBuild\14.0\bin\msbuild.exe` failed with exit code: 1           
  gyp ERR! stack     at ChildProcess.onExit (C:\Users\Marek\AppData\Roaming\npm\node_modules\npm\node_modules\nod
  e-gyp\lib\build.js:276:23)                                                                                     
  gyp ERR! stack     at emitTwo (events.js:87:13)                                                                
  gyp ERR! stack     at ChildProcess.emit (events.js:172:7)                                                      
  gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:200:12)                   
  gyp ERR! System Windows_NT 10.0.10586                                                                          
  gyp ERR! command "C:\\Program Files\\nodejs\\node.exe" "C:\\Users\\Marek\\AppData\\Roaming\\npm\\node_modules\\
  npm\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild"                                                       
  gyp ERR! cwd C:\Users\Marek\WEB\moje-skoly\web-app\node_modules\bufferutil                                     
  gyp ERR! node -v v5.1.1                                                                                        
  gyp ERR! node-gyp -v v3.2.1                                                                                    
  gyp ERR! not ok                                                                                                
  npm WARN install:bufferutil@1.2.1 bufferutil@1.2.1 install: `node-gyp rebuild`                                 
  npm WARN install:bufferutil@1.2.1 Exit status 1                       
  </code></pre>
  
  <p>Previously it failed because of Python 2.7 not installed, now it is this. It's causing me headaches. What should I do about this?</p>