Performing C SOURCE FILE Test CMAKE_HAVE_LIBC_PTHREAD failed with the following output:
Change Dir: /home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/gmake -f Makefile cmTC_ef18d/fast && gmake[1]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'
/usr/bin/gmake  -f CMakeFiles/cmTC_ef18d.dir/build.make CMakeFiles/cmTC_ef18d.dir/build
gmake[2]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_ef18d.dir/src.c.o
/home/buildroot/autobuild/instance-2/output-1/host/bin/aarch64_be-none-linux-gnu-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/aarch64_be-buildroot-linux-gnu/sysroot -DCMAKE_HAVE_LIBC_PTHREAD  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -D_FORTIFY_SOURCE=1   -DNDEBUG -o CMakeFiles/cmTC_ef18d.dir/src.c.o -c /home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp/src.c
Linking C executable cmTC_ef18d
/home/buildroot/autobuild/instance-2/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_ef18d.dir/link.txt --verbose=1
/home/buildroot/autobuild/instance-2/output-1/host/bin/aarch64_be-none-linux-gnu-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/aarch64_be-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -D_FORTIFY_SOURCE=1   -DNDEBUG -latomic  CMakeFiles/cmTC_ef18d.dir/src.c.o -o cmTC_ef18d 
/home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/aarch64_be-none-linux-gnu/10.3.1/../../../../aarch64_be-none-linux-gnu/bin/ld: CMakeFiles/cmTC_ef18d.dir/src.c.o: undefined reference to symbol 'pthread_join@@GLIBC_2.17'
/home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/aarch64_be-none-linux-gnu/10.3.1/../../../../aarch64_be-none-linux-gnu/bin/ld: /home/buildroot/autobuild/instance-2/output-1/host/aarch64_be-buildroot-linux-gnu/sysroot/lib64/libpthread.so.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
gmake[2]: *** [CMakeFiles/cmTC_ef18d.dir/build.make:99: cmTC_ef18d] Error 1
gmake[2]: Leaving directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'
gmake[1]: *** [Makefile:127: cmTC_ef18d/fast] Error 2
gmake[1]: Leaving directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'


Source file was:
#include <pthread.h>

static void* test_func(void* data)
{
  return data;
}

int main(void)
{
  pthread_t thread;
  pthread_create(&thread, NULL, test_func, NULL);
  pthread_detach(thread);
  pthread_cancel(thread);
  pthread_join(thread, NULL);
  pthread_atfork(NULL, NULL, NULL);
  pthread_exit(NULL);

  return 0;
}

Determining if the function pthread_create exists in the pthreads failed with the following output:
Change Dir: /home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/gmake -f Makefile cmTC_150bc/fast && gmake[1]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'
/usr/bin/gmake  -f CMakeFiles/cmTC_150bc.dir/build.make CMakeFiles/cmTC_150bc.dir/build
gmake[2]: Entering directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_150bc.dir/CheckFunctionExists.c.o
/home/buildroot/autobuild/instance-2/output-1/host/bin/aarch64_be-none-linux-gnu-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/aarch64_be-buildroot-linux-gnu/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -D_FORTIFY_SOURCE=1 -DCHECK_FUNCTION_EXISTS=pthread_create  -DNDEBUG -o CMakeFiles/cmTC_150bc.dir/CheckFunctionExists.c.o -c /home/buildroot/autobuild/instance-2/output-1/host/share/cmake-3.22/Modules/CheckFunctionExists.c
Linking C executable cmTC_150bc
/home/buildroot/autobuild/instance-2/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_150bc.dir/link.txt --verbose=1
/home/buildroot/autobuild/instance-2/output-1/host/bin/aarch64_be-none-linux-gnu-gcc --sysroot=/home/buildroot/autobuild/instance-2/output-1/host/aarch64_be-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g0 -D_FORTIFY_SOURCE=1 -DCHECK_FUNCTION_EXISTS=pthread_create  -DNDEBUG -latomic  CMakeFiles/cmTC_150bc.dir/CheckFunctionExists.c.o -o cmTC_150bc  -lpthreads 
/home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/aarch64_be-none-linux-gnu/10.3.1/../../../../aarch64_be-none-linux-gnu/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
gmake[2]: *** [CMakeFiles/cmTC_150bc.dir/build.make:99: cmTC_150bc] Error 1
gmake[2]: Leaving directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'
gmake[1]: *** [Makefile:127: cmTC_150bc/fast] Error 2
gmake[1]: Leaving directory '/home/buildroot/autobuild/instance-2/output-1/build/gqrx-2.14.4/CMakeFiles/CMakeTmp'