Determining if the pthread_create exist failed with the following output:
Change Dir: /users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/gmake "cmTryCompileExec3924680226/fast"
/usr/bin/gmake -f CMakeFiles/cmTryCompileExec3924680226.dir/build.make CMakeFiles/cmTryCompileExec3924680226.dir/build
gmake[1]: Entering directory `/users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec3924680226.dir/CheckSymbolExists.c.o
/usr/bin/cc   -Wall -std=gnu99 -fstack-protector-all     -o CMakeFiles/cmTryCompileExec3924680226.dir/CheckSymbolExists.c.o   -c /users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp/CheckSymbolExists.c
Linking C executable cmTryCompileExec3924680226
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec3924680226.dir/link.txt --verbose=1
/usr/bin/cc    -Wall -std=gnu99 -fstack-protector-all      CMakeFiles/cmTryCompileExec3924680226.dir/CheckSymbolExists.c.o  -o cmTryCompileExec3924680226 -rdynamic 
CMakeFiles/cmTryCompileExec3924680226.dir/CheckSymbolExists.c.o: In function `main':
CheckSymbolExists.c:(.text+0x29): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
gmake[1]: Leaving directory `/users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp'
gmake[1]: *** [cmTryCompileExec3924680226] Error 1
gmake: *** [cmTryCompileExec3924680226/fast] Error 2

File /users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/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: /users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp

Run Build Command:/usr/bin/gmake "cmTryCompileExec1681855900/fast"
/usr/bin/gmake -f CMakeFiles/cmTryCompileExec1681855900.dir/build.make CMakeFiles/cmTryCompileExec1681855900.dir/build
gmake[1]: Entering directory `/users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp'
/usr/bin/cmake -E cmake_progress_report /users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp/CMakeFiles 1
Building C object CMakeFiles/cmTryCompileExec1681855900.dir/CheckFunctionExists.c.o
/usr/bin/cc   -Wall -std=gnu99 -fstack-protector-all  -DCHECK_FUNCTION_EXISTS=pthread_create   -o CMakeFiles/cmTryCompileExec1681855900.dir/CheckFunctionExists.c.o   -c /usr/share/cmake/Modules/CheckFunctionExists.c
Linking C executable cmTryCompileExec1681855900
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTryCompileExec1681855900.dir/link.txt --verbose=1
/usr/bin/cc    -Wall -std=gnu99 -fstack-protector-all  -DCHECK_FUNCTION_EXISTS=pthread_create    CMakeFiles/cmTryCompileExec1681855900.dir/CheckFunctionExists.c.o  -o cmTryCompileExec1681855900 -rdynamic -lpthreads 
/usr/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
gmake[1]: *** [cmTryCompileExec1681855900] Error 1
gmake[1]: Leaving directory `/users/www/rtrlib.realmv6.org/html/doxygen/rtrlib-0.3.6/CMakeFiles/CMakeTmp'
gmake: *** [cmTryCompileExec1681855900/fast] Error 2