Fix SDL2 include path (#196)

The CMake functionality provided by SDL2 specifies that the include
directory is the `SDL2` directory itself, not the parent directory
thereof. On some systems, we're getting lucky because the SDL2 directory
resides in a common include directory like `/usr/include`, so the
include directory given by the SDL2 CMake functionality isn't used. Of
course, on systems where this is not the case, the compiler fails to
find the headers.

Signed-off-by: Scott K Logan <[email protected]>

Author: cottsay

joy/include/joy/joy.hpp

@@ -30,7 +30,7 @@
 #ifndef JOY__JOY_HPP_
 #define JOY__JOY_HPP_
 
-#include <SDL2/SDL.h>
+#include <SDL.h>
 
 #include <rclcpp/rclcpp.hpp>
 #include <sensor_msgs/msg/joy.hpp>

joy/src/joy.cpp

@@ -27,7 +27,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <SDL2/SDL.h>
+#include <SDL.h>
 
 #include <rclcpp/rclcpp.hpp>
 #include <rclcpp_components/register_node_macro.hpp>

joy/src/joy_enumerate_devices.cpp

@@ -29,7 +29,7 @@
 
 // On Windows, we have to be sure that SDL doesn't generate its own main.
 #define SDL_MAIN_HANDLED
-#include <SDL2/SDL.h>
+#include <SDL.h>
 
 #include <cstdio>
 #include <stdexcept>