 &lt;flags&gt; &lt;variables&gt; &lt;targets&gt;</code></pre>
<p><strong>Makefile Variables</strong></p>
<p>Make targets can be preceded by any number of Makefile variable name=value pairs.
For example, to compile <code>../my_dir/my_program.stan</code> for an OpenCL (GPU) machine,
set the makefile variable <code>STAN_OPENCL</code> to <code>TRUE</code>:</p>
<pre><code>&gt; make STAN_OPENCL=TRUE ../my_dir/my_program    # on Windows use mingw32-make</code></pre>
<p>Makefile variables can also be set by creatin