title: Installing pkg-config files to proper path on CentOS with automake
body: <p>I have a couple projects I maintain that are built using automake (let's call them lib1 and lib2).  lib2 is dependent on lib1 as a library and I'm having some issues with the pkg-config defaults on CentOS.  Ideally, I'd like users to not have to set any environment variables to get everything to install properly.</p>
  
  <p>Right now, it's just assuming <code>${PREFIX}/lib/pkgconfig</code> as the destination for my .pc files, but on CentOS 7, the default for <code>${PREFIX}</code> is <code>/usr/local</code> but <code>pkgconfig</code> by default only looks in <code>/usr/share/pkgconfig</code> and <code>/usr/lib64/pkgconfig</code>.  Therefore, <code>lib2</code> can't find <code>lib1</code> with <code>pkg-config</code> and the configure script blows up.</p>
  
  <p>So, the question is, how can my <code>make install</code> in <code>lib1</code> properly detect the directory to install the <code>pkg-config</code> files?</p>