Determining if the pthread_create exist failed with the following output: Change Dir: /home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp Run Build Command:"/usr/bin/make" "cmTC_3c793/fast" make[1]: Entering directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_3c793.dir/build.make CMakeFiles/cmTC_3c793.dir/build make[2]: Entering directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_3c793.dir/CheckSymbolExists.c.o /home/peko/autobuild/instance-0/output/host/bin/aarch64-linux-gcc --sysroot=/home/peko/autobuild/instance-0/output/host/aarch64-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -std=gnu99 -fvisibility=hidden -Wsign-compare -Wall -Wno-uninitialized -DNDEBUG -o CMakeFiles/cmTC_3c793.dir/CheckSymbolExists.c.o -c /home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp/CheckSymbolExists.c Linking C executable cmTC_3c793 /home/peko/autobuild/instance-0/output/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_3c793.dir/link.txt --verbose=1 /home/peko/autobuild/instance-0/output/host/bin/aarch64-linux-gcc --sysroot=/home/peko/autobuild/instance-0/output/host/aarch64-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -std=gnu99 -fvisibility=hidden -Wsign-compare -Wall -Wno-uninitialized -DNDEBUG -rdynamic CMakeFiles/cmTC_3c793.dir/CheckSymbolExists.c.o -o cmTC_3c793 CMakeFiles/cmTC_3c793.dir/CheckSymbolExists.c.o: In function `main': CheckSymbolExists.c:(.text.startup+0x0): undefined reference to `pthread_create' CheckSymbolExists.c:(.text.startup+0x4): undefined reference to `pthread_create' collect2: error: ld returned 1 exit status make[2]: *** [cmTC_3c793] Error 1 make[2]: Leaving directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' make[1]: *** [cmTC_3c793/fast] Error 2 make[1]: Leaving directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' File /home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include int main(int argc, char** argv) { (void)argv; #ifndef pthread_create return ((int*)(&pthread_create))[argc]; #else (void)argc; return 0; #endif } Determining if the function pthread_create exists in the pthreads failed with the following output: Change Dir: /home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp Run Build Command:"/usr/bin/make" "cmTC_03084/fast" make[1]: Entering directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_03084.dir/build.make CMakeFiles/cmTC_03084.dir/build make[2]: Entering directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_03084.dir/CheckFunctionExists.c.o /home/peko/autobuild/instance-0/output/host/bin/aarch64-linux-gcc --sysroot=/home/peko/autobuild/instance-0/output/host/aarch64-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -std=gnu99 -fvisibility=hidden -Wsign-compare -Wall -Wno-uninitialized -DCHECK_FUNCTION_EXISTS=pthread_create -DNDEBUG -o CMakeFiles/cmTC_03084.dir/CheckFunctionExists.c.o -c /home/peko/autobuild/instance-0/output/host/share/cmake-3.8/Modules/CheckFunctionExists.c Linking C executable cmTC_03084 /home/peko/autobuild/instance-0/output/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_03084.dir/link.txt --verbose=1 /home/peko/autobuild/instance-0/output/host/bin/aarch64-linux-gcc --sysroot=/home/peko/autobuild/instance-0/output/host/aarch64-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -std=gnu99 -fvisibility=hidden -Wsign-compare -Wall -Wno-uninitialized -DCHECK_FUNCTION_EXISTS=pthread_create -DNDEBUG -rdynamic CMakeFiles/cmTC_03084.dir/CheckFunctionExists.c.o -o cmTC_03084 -lpthreads /home/peko/autobuild/instance-0/output/host/opt/ext-toolchain/bin/../lib/gcc/aarch64-buildroot-linux-gnu/6.4.0/../../../../aarch64-buildroot-linux-gnu/bin/ld: cannot find -lpthreads collect2: error: ld returned 1 exit status make[2]: *** [cmTC_03084] Error 1 make[2]: Leaving directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp' make[1]: *** [cmTC_03084/fast] Error 2 make[1]: Leaving directory `/home/peko/autobuild/instance-0/output/build/gnuradio-3.7.13.3/buildroot-build/CMakeFiles/CMakeTmp'