add comments and fix tabs

Author: Narukara

libmicroros.mk

@@ -60,6 +60,8 @@ $(EXTENSIONS_DIR)/micro_ros_src/src:
 	git clone -b ros2 https://github.com/eProsima/micro-CDR src/micro-CDR; \
 	git clone -b rolling https://github.com/micro-ROS/rcl src/rcl; \
 	git clone -b rolling https://github.com/ros2/rclc src/rclc; \
+	# https://github.com/ros2/rclc needs to be pinned to an older version until
+	# ros2/rcl#1269 is added in https://github.com/micro-ROS/rcl.
 	cd src/rclc; \
 	git reset --hard 2283a6d76c3f41a964d03610a3305166d8c2caaa; \
 	cd ../..; \
@@ -68,6 +70,7 @@ $(EXTENSIONS_DIR)/micro_ros_src/src:
 	git clone -b rolling https://github.com/micro-ROS/rosidl_typesupport src/rosidl_typesupport; \
 	git clone -b rolling https://github.com/micro-ROS/rosidl_typesupport_microxrcedds src/rosidl_typesupport_microxrcedds; \
 	git clone -b rolling https://github.com/ros2/rosidl src/rosidl; \
+	# https://github.com/ros2/rosidl needs to be pinned to an older version due to breaking changes made with ros2/rosidl#941.
 	cd src/rosidl; \
 	git reset --hard 2e9ab2d70097cbfa5bb48ae4486a8a1c15a3936c; \
 	cd ../..; \
@@ -84,10 +87,10 @@ $(EXTENSIONS_DIR)/micro_ros_src/src:
 	git clone -b rolling https://github.com/ros2/ros2_tracing src/ros2_tracing; \
 	git clone -b rolling https://github.com/micro-ROS/micro_ros_utilities src/micro_ros_utilities; \
 	git clone -b rolling https://github.com/ros2/rosidl_core src/rosidl_core; \
-  	touch src/rosidl/rosidl_typesupport_introspection_cpp/COLCON_IGNORE; \
-  	touch src/rcl_logging/rcl_logging_implementation/COLCON_IGNORE; \
-  	touch src/rcl_logging/rcl_logging_spdlog/COLCON_IGNORE; \
-  	touch src/rclc/rclc_examples/COLCON_IGNORE; \
+	touch src/rosidl/rosidl_typesupport_introspection_cpp/COLCON_IGNORE; \
+	touch src/rcl_logging/rcl_logging_implementation/COLCON_IGNORE; \
+	touch src/rcl_logging/rcl_logging_spdlog/COLCON_IGNORE; \
+	touch src/rclc/rclc_examples/COLCON_IGNORE; \
 	touch src/rcl/rcl_yaml_param_parser/COLCON_IGNORE; \
 	touch src/ros2_tracing/test_tracetools/COLCON_IGNORE; \
 	touch src/ros2_tracing/lttngpy/COLCON_IGNORE; \