rnal or external command</code></pre>
<p>To fix this, you should make sure that the RTools installation is
in your <code>PATH</code> environment variable.
In addition, if you have the RTools 4.0 toolchain, then call the utility <code>pacman</code>
to register the right version of make:</p>
<pre><code>pacman -Sy mingw-w64-x86_64-make</code></pre>
<p>See: <a href="https://discourse.mc-stan.org/t/cmdstan-installation-on-windows/11287/6" class="uri">https://discourse.mc-stan.org/t/cmdstan-installation-on-window