title: Linker wants library that I already linked
body: <pre><code>[1/2] g++ -std=gnu++11 -Wall -g -I/usr/local/include -c test.cpp -o test.o
  [2/2] g++ -std=gnu++11 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64 -glog -lfolly test.o -o hello
  FAILED: g++ -std=gnu++11 -L/usr/local/lib64 -Wl,-rpath,/usr/local/lib64 -glog -lfolly test.o -o hello
  /usr/bin/ld: /usr/local/lib64/libfolly.so: undefined reference to symbol '_ZN6google15LogMessageFatalD1Ev'
  /usr/bin/ld: note: '_ZN6google15LogMessageFatalD1Ev' is defined in DSO /usr/local/lib64/libglog.so.0 so try adding it to the linker command line
  /usr/local/lib64/libglog.so.0: could not read symbols: Invalid operation
  collect2: error: ld returned 1 exit status
  </code></pre>
  
  <p><code>libglog</code> sits inside <code>/usr/local/lib64</code> just like <code>libfolly</code>. For some reason it "could not read symbols" on the glog library. Why not? I already tried adding all of these with no change: <code>-ldl -lc -lpthread -lrt</code>
  As I don't really know why they should be necessary, I left them out from the output above.</p>