title: ggplot axes are garbled, look like Unicode boxes
body: <p>Running Ubuntu 16.04; R 3.6.2; ggplot2 3.3.0</p>
  <p>Running R under --nix</p>
  <p>If I run this ..</p>
  <pre><code>library(ggplot2)
  data(&quot;midwest&quot;, package = &quot;ggplot2&quot;)
  ggplot(midwest, aes(x=area, y=poptotal))
  </code></pre>
  <p>I get a plot with little boxes for the axes (Unicode?)</p>
  <p><a href="https://i.stack.imgur.com/YFX0R.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YFX0R.png" alt="ggplot with garbled axes" /></a></p>
  <p>I get the same little boxes if I use 'plot'</p>
  <p><em>But</em> If I run 'plot' add a 'family' attribute,</p>
  <pre><code>plot (1:10, family=&quot;arial&quot;) 
  </code></pre>
  <p>I get this (nice axes),</p>
  <p><a href="https://i.stack.imgur.com/vE8F1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vE8F1.png" alt="plot gives good axes with 'family' attribute" /></a></p>
  <p>This shows that at least <em>some</em> fonts are there!</p>
  <p>Back to ggplot ....</p>
  <p>The easy solution would be to figure out (I tried) how to set the family in ggplot.</p>
  <p>I tried,</p>
  <pre><code>ggplot(heightweight, aes(x= ageYear, y=heightIn, font=&quot;ariel&quot;)) + geom_point() 
  ggplot(heightweight, aes(x= ageYear, y=heightIn, family=&quot;ariel&quot;)) + geom_point() 
  </code></pre>
  <p>No help .. Little boxes.
  Note: It's happy if I put family=&quot;Zombie&quot;</p>
  <p>Anyone know how to set the family in ggplot?</p>
  <p>A better solution?</p>
  <p>The hard solution would be for me to figure out which fonts are missing, install them under --nix, and then make sure R (under --nix) can find them.</p>