Adding external c library to a ROS2 node

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I am using ROS2 foxy on a headless Ubuntu 20.04.1 LTS. I would like to use an external c library(Gstreamer library) in the node C++ code.

I included the the library in the node code as follows:

extern "C" {
#include "gst/gst.h"
}

In the package.xml file I added:

 <depend>libgstreamer1.0-dev</depend>
  <depend>libgstreamer-plugins-base1.0-dev</depend>

And in the CMakeList.txt file I added:

find_package(PkgConfig)
pkg_check_modules(GSTREAMER REQUIRED gstreamer-1.0
                    gstreamer-app-1.0)
add_executable(server src/my_server.cpp)
ament_target_dependencies(server
    rclcpp my_interfaces "${GSTREAMER}")

However, every time I run colcon build I get

fatal error: gst/gst.h: No such file or directory
    5 | #include "gst/gst.h"
      |          ^~~~~~~~~~~

gst.h can be found in /usr/include/gstreamer-1.0/gst

How can I link against this library and what is the best practice for adding external libraries in ROS2 in general. Thanks