Determining if the pthread_create exist failed with the following output:
Change Dir: /home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/make "cmTryCompileExec3440868673/fast"
/usr/bin/make -f CMakeFiles/cmTryCompileExec3440868673.dir/build.make CMakeFiles/cmTryCompileExec3440868673.dir/build
make[1]: Entering directory `/home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec3440868673.dir/CheckSymbolExists.c.o
/usr/bin/cc    -o CMakeFiles/cmTryCompileExec3440868673.dir/CheckSymbolExists.c.o   -c /home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp/CheckSymbolExists.c
Linking C executable cmTryCompileExec3440868673
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec3440868673.dir/link.txt --verbose=1
/usr/bin/cc       CMakeFiles/cmTryCompileExec3440868673.dir/CheckSymbolExists.c.o  -o cmTryCompileExec3440868673 -rdynamic
CMakeFiles/cmTryCompileExec3440868673.dir/CheckSymbolExists.c.o: In function `main':
CheckSymbolExists.c:(.text+0x16): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
make[1]: Leaving directory `/home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp'
make[1]: *** [cmTryCompileExec3440868673] Error 1
make: *** [cmTryCompileExec3440868673/fast] Error 2

File /home/naor/Desktop/glfw-3.1.1/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/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/make "cmTryCompileExec3942061042/fast"
/usr/bin/make -f CMakeFiles/cmTryCompileExec3942061042.dir/build.make CMakeFiles/cmTryCompileExec3942061042.dir/build
make[1]: Entering directory `/home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec3942061042.dir/CheckFunctionExists.c.o
/usr/bin/cc   -DCHECK_FUNCTION_EXISTS=pthread_create   -o CMakeFiles/cmTryCompileExec3942061042.dir/CheckFunctionExists.c.o   -c /usr/share/cmake-2.8/Modules/CheckFunctionExists.c
Linking C executable cmTryCompileExec3942061042
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec3942061042.dir/link.txt --verbose=1
/usr/bin/cc   -DCHECK_FUNCTION_EXISTS=pthread_create    CMakeFiles/cmTryCompileExec3942061042.dir/CheckFunctionExists.c.o  -o cmTryCompileExec3942061042 -rdynamic -lpthreads
/usr/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
make[1]: Leaving directory `/home/naor/Desktop/glfw-3.1.1/CMakeFiles/CMakeTmp'
make[1]: *** [cmTryCompileExec3942061042] Error 1
make: *** [cmTryCompileExec3942061042/fast] Error 2