Makefile with source get error `No such file or directory` : <p>I have a really simple <code>Makefile</code> that's doing <code>source</code> to set ENV variables. But it doesn't work if I call it from <code>Makefile</code></p>

<p>I get this error</p>

<pre><code>make dev
source ./bin/authenticate.sh
make: source: No such file or directory
make: *** [dev] Error 1
</code></pre>

<p>The script exists. </p>

<p>If I run this in command-line it works. </p>

<pre><code>source ./bin/authenticate.sh
Works!
</code></pre>

<p>This is my <code>Makefile</code></p>

<pre><code>test:
    pytest -s

dev:
    source ./bin/authenticate.sh
</code></pre>

<p>I'm using OSX. I'm not sure if this would make a difference.</p>
