title: Pkg-config path looks in the correct directory, but isn't finding the .pc file
body: <p>I'm trying to build SWUpdater from a MakeFile, but when building get the error</p>
  
  <pre><code>Package lua was not found in the pkg-config search path.
  Perhaps you should add the directory containing `lua.pc'
  to the PKG_CONFIG_PATH environment variable
  No package 'lua' found
  Package lua was not found in the pkg-config search path.
  Perhaps you should add the directory containing `lua.pc'
  to the PKG_CONFIG_PATH environment variable
  No package 'lua' found
  Package lua was not found in the pkg-config search path.
  Perhaps you should add the directory containing `lua.pc'
  to the PKG_CONFIG_PATH environment variable
  No package 'lua' found
  make: 'Makefile' is up to date.
  </code></pre>
  
  <p>From what I've read online, what this error is telling me is that when the system is looking for all the files SWUpdate depends on it isn't able to find the <code>lua.pc</code> file in any of the places <code>pkg-config</code> looks.</p>
  
  <p>I looked in <code>usr/lib/pkgconfig</code> and found the <code>lu50.pc</code> and <code>lualib50.pc</code> files in that directory. I looked at where the package configure-er looks using</p>
  
  <pre><code>pkg-config --variable pc_path pkg-config
  </code></pre>
  
  <p>Which told me that it looks in <code>/usr/lib/pkgconfig</code>, among other places. I saw someone else mention that you can check the <code>PKG_CONFIG_PATH</code> variable to see what that's set to. I checked and it was blank, so I thought I would just set the path to <code>/usr/lib/pkgconfig</code> with</p>
  
  <pre><code>export PKG_CONFIG_PATH=/usr/lin/pkgconfig
  </code></pre>
  
  <p>I checked the path, and ran the <code>make</code> command again but the same error occurred.</p>
  
  <p>As a last ditch effort to fix this I moved the <code>lua50.pc</code> and <code>lualib50.pc</code> files to another directory that was listed as in the package configure-er path to see if that helped anything, but the same error occurred, so I moved them back to where they were originally.</p>
  
  <p>So my main question here is: Why isn't the package configure-er finding the <code>lua50.pc</code> file despite it looking in the correct directory?</p>
  
  <p><strong>EDIT</strong>: I have managed to get around the errors by simply renaming <code>lua50.pc</code> as <code>lua.pc</code>, which leads me to believe that the reason it could not find it is because it was literally looking for a file named <code>lua.pc</code> instead of a general lua pc file. This aside, my question still remains since I have a feeling in my gut that this isn't a long-term viable solution.</p>