tl;dr - CMake fails at linker not finding System library with precompiled RaspberryPi toolchain when other libraries work
So I've been fighting this for a few days, and I believe I'm nearing the end of my journey to get an ARM executable for the RaspberryPi compiled through CMake on macOS Sierra.
Currently, I'm using the pre-compiled RaspberryPi toolchain from this blog, and getting the following results:
macbook:gpsexample alex$ cmake .
-- Configuring done
-- Generating done
-- Build files have been written to: /Volumes/linuxdev/gpsexample
macbook:gpsexample alex$ make
[ 20%] Linking C executable gpsexample
clang: warning: argument unused during compilation: '-pthread' [-Wunused-command-line-argument]
ld: library not found for -lSystem
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [gpsexample] Error 1
make[1]: *** [CMakeFiles/gpsexample.dir/all] Error 2
make: *** [all] Error 2
I've previously had problems linking the m library with the same error, however adding the proper system root fixed that issue. I have a feeling I'm missing another library or directory - however I'm not too sure where.
Below is my CMakeLists.txt (single file only):
cmake_minimum_required(VERSION 3.6.2)
project (gpsexample)
set(CMAKE_SYSROOT "/Volumes/xtools/armv8-rpi3-linux-gnueabihf/armv8-rpi3-linux-gnueabihf/sysroot")
#Enable POSIX Threading
set(THREADS_PREFER_PTHREAD_FLAG ON)
find_package(Threads REQUIRED)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")
#Bring the headers in
include_directories(include)
#Wildcard add all source files in dir
file(GLOB SOURCES "src/*.c")
#Create the target
add_executable(gpsexample ${SOURCES})
#Link the standard math lib to the exec
target_link_libraries(gpsexample m)
Is there somewhere else I should add for a library to get System found? Will I need to download the raw files from the Pi directly and include them in the custom tools directory?
Thanks for all the help.
