title: Makefile.vc(18) : fatal error U1050: Unable to auto-detect toolchain architecture! If cl.exe is in your PATH rerun nmake with ARCH=<arch>. Stop
body: <p>I'm trying to build <code>libwebp.dll</code> for webp, using <a href="http://www.kopf.com.br/kaplof/libwebp-dll-binaries-for-windows-download-missing/" rel="nofollow noreferrer">these instructions</a>  (I downloaded this <a href="https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.0.0.tar.gz" rel="nofollow noreferrer">source code</a>)</p>
  
  <p>However, I'm getting the error: </p>
  
  <blockquote>
    <p>Makefile.vc(18) : fatal error U1050: Unable to auto-detect toolchain architecture! If cl.exe is in your PATH rerun nmake with ARCH=. Stop.` </p>
  </blockquote>
  
  <p>on command <code>nmake /f Makefile.vc CFG=release-dynamic RTLIBCFG=dynamic OBJDIR=output</code> in the Developer Command Prompt for Visual Studio 2017 (Community Edition).</p>
  
  <p>I don't see file <code>cl.exe</code> anywhere in <code>C:\Program Files (x86)\Microsoft Visual Studio 14.0</code></p>
  
  <p>How can I fix this?</p>