Determining if the pthread_create exist failed with the following output:
Change Dir: /home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_4dfeb/fast"
/usr/bin/make -f CMakeFiles/cmTC_4dfeb.dir/build.make CMakeFiles/cmTC_4dfeb.dir/build
make[1]: Entering directory '/home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_4dfeb.dir/CheckSymbolExists.c.o
/usr/bin/cc     -o CMakeFiles/cmTC_4dfeb.dir/CheckSymbolExists.c.o   -c /home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp/CheckSymbolExists.c
Linking C executable cmTC_4dfeb
/usr/local/bin/cmake -E cmake_link_script CMakeFiles/cmTC_4dfeb.dir/link.txt --verbose=1
/usr/bin/cc       CMakeFiles/cmTC_4dfeb.dir/CheckSymbolExists.c.o  -o cmTC_4dfeb -rdynamic 
CMakeFiles/cmTC_4dfeb.dir/CheckSymbolExists.c.o: In function `main':
CheckSymbolExists.c:(.text+0x16): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_4dfeb.dir/build.make:97: recipe for target 'cmTC_4dfeb' failed
make[1]: *** [cmTC_4dfeb] Error 1
make[1]: Leaving directory '/home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_4dfeb/fast' failed
make: *** [cmTC_4dfeb/fast] Error 2

File /home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
/* */
#include <pthread.h>

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/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_41756/fast"
/usr/bin/make -f CMakeFiles/cmTC_41756.dir/build.make CMakeFiles/cmTC_41756.dir/build
make[1]: Entering directory '/home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_41756.dir/CheckFunctionExists.c.o
/usr/bin/cc    -DCHECK_FUNCTION_EXISTS=pthread_create   -o CMakeFiles/cmTC_41756.dir/CheckFunctionExists.c.o   -c /usr/local/share/cmake-3.7/Modules/CheckFunctionExists.c
Linking C executable cmTC_41756
/usr/local/bin/cmake -E cmake_link_script CMakeFiles/cmTC_41756.dir/link.txt --verbose=1
/usr/bin/cc   -DCHECK_FUNCTION_EXISTS=pthread_create    CMakeFiles/cmTC_41756.dir/CheckFunctionExists.c.o  -o cmTC_41756 -rdynamic -lpthreads 
/usr/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_41756.dir/build.make:97: recipe for target 'cmTC_41756' failed
make[1]: *** [cmTC_41756] Error 1
make[1]: Leaving directory '/home/lorenzo/Scrivania/Varie/repo/xmr-stak-amd/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_41756/fast' failed
make: *** [cmTC_41756/fast] Error 2