libPacerGazeboPlugin.so not installed

[hsu]

in install target, I only see libPacer.so, but not libPacerGazeboPlugin.so, so launch gazebo example fails with

[Err] [Plugin.hh:153] Failed to load plugin libPacerGazeboPlugin.so: libPacerGazeboPlugin.so: cannot open shared object file: No such file or directory