title: Makefile:252: recipe for target 'install' failed
body: <p>I'm trying to install pwlib on my asterisk/ubuntu 16.04 Server, but when I try to run <code>make install</code> I get the following error message:</p>
  
  <pre><code>( for dir in /usr/local/lib \
               /usr/local/bin \
               /usr/local/include/ptlib \
                       /usr/local/include/ptlib/unix/ptlib \
                       /usr/local/include/ptclib \
                       /usr/local/share/pwlib/make ; \
          do mkdir -p $dir ; chmod 755 $dir ; \
  done )
  /usr/bin/install -c -m 444 lib/libpt_linux_x86_64_r.so.1.12.0 /usr/local/lib
  /usr/bin/install: cannot stat 'lib/libpt_linux_x86_64_r.so.1.12.0': No such file or directory
  Makefile:252: recipe for target 'install' failed
  make: *** [install] Error 1
  </code></pre>
  
  <p>Thank you in advance for your help!</p>
  
  <p>Greetings</p>
  
  <p>Alessio</p>