How do you install actionlib from source in an existing workspace?

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I've built my base Kinetic packages as outlined in the wiki, but when I went to run a custom package, I received the error:

Could not find a package configuration file provided by "actionlib" with
any of the following names:

actionlibConfig.cmake
actionlib-config.cmake

So I tried to add actionlib to my original workspace source and rebuild by doing:

cd ~/ros_catkin_ws
rosinstall_generator actionlib --rosdistro kinetic --deps | wstool merge -t src -
wstool update -t src -j2 --delete-changed-uris
./src/catkin/bin/catkin_make_isolated --install -DCMAKE_BUILD_TYPE=Release --install-space /opt/ros/kinetic -j1

However, after rebuilding, rospack list | grep -i actionlib still shows no actionlib package installed.

What am I doing wrong?