title: Electron throwing error %1 is not a valid win32 application with custom node addon
body: <p>I've written a custom node addon that works perfectly fine when running the 64 bit version of Electron.
  I tried setting the architecture to ia32 and everything builds, but I get the not valid win32 application error, no matter what I do.</p>
  
  <p>My environment settings are:</p>
  
  <pre><code>npm_config_disturl=https://atom.io/download/atom-shell
  set npm_config_target=1.0.1
  set npm_config_arch=ia32
  set npm_config_runtime=electron
  set HOME="C:\Users\myHome\.electron-gyp"
  set VCTargetsPath=C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140
  </code></pre>
  
  <p>I have been building the addon by calling npm install.</p>