title: R package requiring the 'libquadmath' library
body: <p>I made a R package which uses <code>Rcpp</code> and which requires the <code>libquadmath</code> library (to use the multiprecision numbers of <code>boost</code>). On my personal laptop (Ubuntu 18.04), it works &quot;as is&quot;. On <code>win-builder</code> it works by setting <code>PKGLIBS = -lquadmath</code> or <code>PKGLIBS = $(FLIBS)</code> in the <code>Makevars</code> file. But I also checked on <code>r-hub</code> with these settings and for the Fedora Linux distribution (R-devel, clang, gfortran) I get a failure.</p>
  <p>This failure is:</p>
  <pre><code>/home/docker/R/BH/include/boost/multiprecision/float128.hpp:40:10: fatal error: 'quadmath.h' file not found
  </code></pre>
  <p>So I'm fearing that my package will not pass the CRAN checks. What is the way to go?</p>