Hi all!

I'm a total ROS beginner and want to compile a tutorial sample for an aarch64 target. Compiling the sample for x86_64 is working fine. In the ROS wiki I found how to start with a cross compiling project. So I created a rostoolchain.cmake like

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_VERSION 1)
set(CMAKE_SYSTEM_PROCESSOR aarch64)

set(CMAKE_C_COMPILER /usr/bin/aarch64-linux-gnu-gcc)
set(CMAKE_CXX_COMPILER /usr/bin/aarch64-linux-gnu-g++)
set(CMAKE_FIND_ROOT_PATH /opt/ros/kinetic /usr/aarch64-linux-gnu)

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM BOTH)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

set(CMAKE_LIBRARY_PATH /usr/lib/aarch64-linux-gnu /usr/aarch64-linux-gnu/lib)
set(CMAKE_IGNORE_PATH /usr/lib/x86_64-linux-gnu/ /usr/lib/x86_64-linux-gnu/lib/)

Starting compilation first creates a warning:

CMake Warning at rostest/CMakeLists.txt:45 (add_executable):
Cannot generate a safe runtime search path for target talker because files
in some directories may conflict with libraries in implicit directories:
runtime library [libpthread.so] in /usr/aarch64-linux-gnu/lib may be hidden by files in:
  /usr/lib/x86_64-linux-gnu
Some of these libraries may not be found correctly.

A little bit later I get an error:

/usr/lib/x86_64-linux-gnu/libboost_signals.so: error adding symbols: File in wrong format

Obviously the aarch64 library file cannot be found although it is available. It seems that the linker is always trying to link the standard x8664 library even if the CMAKEIGNORE_PATH is set. Can anyone tell me how to exclude the standard library?

Any help is appreciated. Thanks.