message: Update README with shared library tip
  A GPDB developer who uses CentOS 6 recently requested we add a tip to our README about adding /usr/local/lib to the list of directories in which the program loader looks.
diff: @@ -296,6 +296,9 @@ Build and install:
  ninja install -C build
  ```
  +### Common Issues
  +
  +Note that because Red Hat-based systems do not normally look for shared libraries in `/usr/local/lib`, it is suggested to add `/usr/local/lib` to the /etc/ld.so.conf if developing on one of these Linux distributions.
  ## Cleanup
  