Performing C SOURCE FILE Test CMAKE_HAVE_LIBC_PTHREAD failed with the following output:
Change Dir: /home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_5fb40/fast && make[1]: Entering directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_5fb40.dir/build.make CMakeFiles/cmTC_5fb40.dir/build
make[2]: Entering directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_5fb40.dir/src.c.o
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/x86_64-amd-linux-gnu-gcc --sysroot=/home/giuliobenetti/autobuild/run/instance-2/output-1/host/x86_64-buildroot-linux-gnu/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -D_FORTIFY_SOURCE=1 -DCMAKE_HAVE_LIBC_PTHREAD  -DNDEBUG   -o CMakeFiles/cmTC_5fb40.dir/src.c.o   -c /home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp/src.c
Linking C executable cmTC_5fb40
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_5fb40.dir/link.txt --verbose=1
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/x86_64-amd-linux-gnu-gcc --sysroot=/home/giuliobenetti/autobuild/run/instance-2/output-1/host/x86_64-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -D_FORTIFY_SOURCE=1 -DCMAKE_HAVE_LIBC_PTHREAD  -DNDEBUG    CMakeFiles/cmTC_5fb40.dir/src.c.o  -o cmTC_5fb40 
CMakeFiles/cmTC_5fb40.dir/src.c.o: In function `main':
src.c:(.text.startup+0x15): undefined reference to `pthread_create'
src.c:(.text.startup+0x1f): undefined reference to `pthread_detach'
src.c:(.text.startup+0x2b): undefined reference to `pthread_join'
src.c:(.text.startup+0x36): undefined reference to `pthread_atfork'
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_5fb40.dir/build.make:86: recipe for target 'cmTC_5fb40' failed
make[2]: *** [cmTC_5fb40] Error 1
make[2]: Leaving directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'
Makefile:121: recipe for target 'cmTC_5fb40/fast' failed
make[1]: *** [cmTC_5fb40/fast] Error 2
make[1]: Leaving directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'


Source file was:
#include <pthread.h>

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

int main(void)
{
  pthread_t thread;
  pthread_create(&thread, NULL, test_func, NULL);
  pthread_detach(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/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_9ab0b/fast && make[1]: Entering directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_9ab0b.dir/build.make CMakeFiles/cmTC_9ab0b.dir/build
make[2]: Entering directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_9ab0b.dir/CheckFunctionExists.c.o
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/x86_64-amd-linux-gnu-gcc --sysroot=/home/giuliobenetti/autobuild/run/instance-2/output-1/host/x86_64-buildroot-linux-gnu/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -D_FORTIFY_SOURCE=1 -DCHECK_FUNCTION_EXISTS=pthread_create  -DNDEBUG   -o CMakeFiles/cmTC_9ab0b.dir/CheckFunctionExists.c.o   -c /home/giuliobenetti/autobuild/run/instance-2/output-1/host/share/cmake-3.15/Modules/CheckFunctionExists.c
Linking C executable cmTC_9ab0b
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_9ab0b.dir/link.txt --verbose=1
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/bin/x86_64-amd-linux-gnu-gcc --sysroot=/home/giuliobenetti/autobuild/run/instance-2/output-1/host/x86_64-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -D_FORTIFY_SOURCE=1 -DCHECK_FUNCTION_EXISTS=pthread_create  -DNDEBUG    CMakeFiles/cmTC_9ab0b.dir/CheckFunctionExists.c.o  -o cmTC_9ab0b -lpthreads 
/home/giuliobenetti/autobuild/run/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/x86_64-amd-linux-gnu/6.2.0/../../../../x86_64-amd-linux-gnu/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_9ab0b.dir/build.make:86: recipe for target 'cmTC_9ab0b' failed
make[2]: *** [cmTC_9ab0b] Error 1
make[2]: Leaving directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'
Makefile:121: recipe for target 'cmTC_9ab0b/fast' failed
make[1]: *** [cmTC_9ab0b/fast] Error 2
make[1]: Leaving directory '/home/giuliobenetti/autobuild/run/instance-2/output-1/build/domoticz-2020.1/CMakeFiles/CMakeTmp'