Build failed on ESP-IDF 5.5 - due to flags being passed via response file

[Narukara]

ESP-IDF 5.5.4 uses response files for compiler and linker flags. It might originate from this commit.

As a result, these two variables

micro_ros_espidf_component/libmicroros.mk

Lines 13 to 14 in b690e1c

	CFLAGS_INTERNAL := $(X_CFLAGS) -ffunction-sections -fdata-sections
	CXXFLAGS_INTERNAL := $(X_CXXFLAGS) -ffunction-sections -fdata-sections

will become:

@"/path-to/micro_ros_espidf_component/examples/int32_publisher/build/toolchain/cflags" -ffunction-sections -fdata-sections
@"/path-to/micro_ros_espidf_component/examples/int32_publisher/build/toolchain/cxxflags" -ffunction-sections -fdata-sections

which corrupts these two sed commands:

micro_ros_espidf_component/libmicroros.mk

Lines 30 to 31 in b690e1c

	sed "s/@CFLAGS@/$(subst /,\/,$(CFLAGS_INTERNAL))/g" | \
	sed "s/@CXXFLAGS@/$(subst /,\/,$(CXXFLAGS_INTERNAL))/g" | \

An empty esp32_toolchain.cmake will be generated.

The build will end with an error message like this:

--- stderr: microxrcedds_client
In file included from /path-to/micro_ros_espidf_component/micro_ros_src/src/Micro-XRCE-DDS-Client/include/uxr/client/transport.h:24,
                 from /path-to/micro_ros_espidf_component/micro_ros_src/src/Micro-XRCE-DDS-Client/include/uxr/client/util/ping.h:28,
                 from /path-to/micro_ros_espidf_component/micro_ros_src/src/Micro-XRCE-DDS-Client/src/c/util/ping.c:1:
/path-to/micro_ros_espidf_component/micro_ros_src/src/Micro-XRCE-DDS-Client/include/uxr/client/profile/transport/ip/udp/udp_transport_posix.h:24:10: fatal error: sys/socket.h: No such file or directory
   24 | #include <sys/socket.h>
      |          ^~~~~~~~~~~~~~
compilation terminated.
gmake[3]: *** [CMakeFiles/microxrcedds_client.dir/build.make:286: CMakeFiles/microxrcedds_client.dir/src/c/util/ping.c.o] Error 1
gmake[3]: *** Waiting for unfinished jobs....
gmake[2]: *** [CMakeFiles/Makefile2:83: CMakeFiles/microxrcedds_client.dir/all] Error 2
gmake[1]: *** [Makefile:136: all] Error 2
---
Failed   <<< microxrcedds_client [1.04s, exited with code 2]
Aborted  <<< rosidl_runtime_c [0.56s]
Aborted  <<< rosidl_parser [0.01s]
Aborted  <<< rcl_logging_interface [0.64s]
Aborted  <<< tracetools_test [0.58s]

Summary: 12 packages finished [2.74s]
  1 package failed: microxrcedds_client
  4 packages aborted: rcl_logging_interface rosidl_parser rosidl_runtime_c tracetools_test
  7 packages had stderr output: microxrcedds_client rcutils ros2trace tracetools_launch tracetools_read tracetools_test tracetools_trace
  48 packages not processed
make: *** [libmicroros.mk:89: /path-to/micro_ros_espidf_component/micro_ros_src/install] Error 2
CMake Error at /path-to/micro_ros_espidf_component/CMakeLists.txt:90 (message):
  FAILED: 2


-- Configuring incomplete, errors occurred!
See also "/path-to/micro_ros_espidf_component/examples/int32_publisher/build/CMakeFiles/CMakeOutput.log".
See also "/path-to/micro_ros_espidf_component/examples/int32_publisher/build/CMakeFiles/CMakeError.log".
cmake failed with exit code 1, output of the command is in the /path-to/micro_ros_espidf_component/examples/int32_publisher/build/log/idf_py_stderr_output_40569 and /path-to/micro_ros_espidf_component/examples/int32_publisher/build/log/idf_py_stdout_output_40569

[Narukara]

It appears that @CFLAGS@ and @CXXFLAGS@ in esp32_toolchain.cmake.in have been deprecated since this commit. Therefore, a simple fix is ​​to remove those two sed commands and related code.