Determining if the pthread_create exist failed with the following output:
Change Dir: /tmp/luxrays/build/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/gmake "cmTryCompileExec3887965564/fast"
/usr/bin/gmake -f CMakeFiles/cmTryCompileExec3887965564.dir/build.make CMakeFiles/cmTryCompileExec3887965564.dir/build
gmake[1]: Entering directory `/tmp/luxrays/build/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /tmp/luxrays/build/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec3887965564.dir/CheckSymbolExists.c.o
/usr/bin/cc   -O3 -march=amdfam10     -o CMakeFiles/cmTryCompileExec3887965564.dir/CheckSymbolExists.c.o   -c /tmp/luxrays/build/CMakeFiles/CMakeTmp/CheckSymbolExists.c
Linking C executable cmTryCompileExec3887965564
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec3887965564.dir/link.txt --verbose=1
/usr/bin/cc  -O3 -march=amdfam10      CMakeFiles/cmTryCompileExec3887965564.dir/CheckSymbolExists.c.o  -o cmTryCompileExec3887965564 -rdynamic 
CMakeFiles/cmTryCompileExec3887965564.dir/CheckSymbolExists.c.o: In function `main':
CheckSymbolExists.c:(.text.startup+0x6): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
gmake[1]: *** [cmTryCompileExec3887965564] Error 1
gmake[1]: Leaving directory `/tmp/luxrays/build/CMakeFiles/CMakeTmp'
gmake: *** [cmTryCompileExec3887965564/fast] Error 2

File /tmp/luxrays/build/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: /tmp/luxrays/build/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/gmake "cmTryCompileExec1740855655/fast"
/usr/bin/gmake -f CMakeFiles/cmTryCompileExec1740855655.dir/build.make CMakeFiles/cmTryCompileExec1740855655.dir/build
gmake[1]: Entering directory `/tmp/luxrays/build/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /tmp/luxrays/build/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec1740855655.dir/CheckFunctionExists.c.o
/usr/bin/cc   -O3 -march=amdfam10  -DCHECK_FUNCTION_EXISTS=pthread_create   -o CMakeFiles/cmTryCompileExec1740855655.dir/CheckFunctionExists.c.o   -c /usr/share/cmake-2.8/Modules/CheckFunctionExists.c
Linking C executable cmTryCompileExec1740855655
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec1740855655.dir/link.txt --verbose=1
/usr/bin/cc  -O3 -march=amdfam10  -DCHECK_FUNCTION_EXISTS=pthread_create    CMakeFiles/cmTryCompileExec1740855655.dir/CheckFunctionExists.c.o  -o cmTryCompileExec1740855655 -rdynamic -lpthreads 
/usr/lib64/gcc/x86_64-slackware-linux/4.7.1/../../../../x86_64-slackware-linux/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
gmake[1]: *** [cmTryCompileExec1740855655] Error 1
gmake[1]: Leaving directory `/tmp/luxrays/build/CMakeFiles/CMakeTmp'
gmake: *** [cmTryCompileExec1740855655/fast] Error 2