try detecting umble in the build farm

Author: facontidavide

src/CMakeLists.txt

@@ -44,7 +44,10 @@ target_link_libraries( DataStreamROS2  commonROS)
 add_library( TopicPublisherROS2 SHARED TopicPublisherROS2/publisher_ros2.cpp)
 target_link_libraries( TopicPublisherROS2 commonROS)
 
-if("$ENV{ROS_DISTRO}" STREQUAL "humble")
+message("AMENT_PREFIX_PATH = ${AMENT_PREFIX_PATH}")
+message("ROS_DISTRO (env) = $ENV{ROS_DISTRO}")
+
+if("${AMENT_PREFIX_PATH}" STREQUAL "/opt/ros/humble" OR "$ENV{ROS_DISTRO}" STREQUAL "humble")
         message(STATUS "Detected Humble")
         target_compile_definitions(DataLoadROS2 PUBLIC ROS_HUMBLE)
         target_compile_definitions(TopicPublisherROS2 PUBLIC ROS_HUMBLE)