Determining if the function pthread_create exists in the pthreads failed with the following output:
Change Dir: /home/lab1_5/ws/ws_linux/build/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/make "cmTryCompileExec/fast"
/usr/bin/make -f CMakeFiles/cmTryCompileExec.dir/build.make CMakeFiles/cmTryCompileExec.dir/build
make[1]: Entering directory `/home/lab1_5/ws/ws_linux/build/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /home/lab1_5/ws/ws_linux/build/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec.dir/CheckFunctionExists.c.o
/usr/bin/gcc   -DCHECK_FUNCTION_EXISTS=pthread_create   -o CMakeFiles/cmTryCompileExec.dir/CheckFunctionExists.c.o   -c /usr/share/cmake-2.8/Modules/CheckFunctionExists.c
Linking C executable cmTryCompileExec
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec.dir/link.txt --verbose=1
/usr/bin/gcc     -DCHECK_FUNCTION_EXISTS=pthread_create    CMakeFiles/cmTryCompileExec.dir/CheckFunctionExists.c.o  -o cmTryCompileExec -rdynamic -lpthreads 
/usr/bin/ld: cannot find -lpthreads
collect2: ld returned 1 exit status
make[1]: *** [cmTryCompileExec] Error 1
make[1]: Leaving directory `/home/lab1_5/ws/ws_linux/build/CMakeFiles/CMakeTmp'
make: *** [cmTryCompileExec/fast] Error 2