Determining if the pthread_setname_np exist failed with the following output:
Change Dir: /home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_f02c1/fast"
make[1]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_f02c1.dir/build.make CMakeFiles/cmTC_f02c1.dir/build
make[2]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_f02c1.dir/CheckSymbolExists.c.o
/home/buildroot/autobuild/instance-0/output-1/host/bin/arm-buildroot-linux-gnueabihf-gcc --sysroot=/home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabihf/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DNDEBUG -fPIE   -o CMakeFiles/cmTC_f02c1.dir/CheckSymbolExists.c.o   -c /home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c
/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c: In function 'main':
/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19: error: 'pthread_setname_np' undeclared (first use in this function); did you mean 'pthread_setcanceltype'?
    8 |   return ((int*)(&pthread_setname_np))[argc];
      |                   ^~~~~~~~~~~~~~~~~~
      |                   pthread_setcanceltype
/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19: note: each undeclared identifier is reported only once for each function it appears in
CMakeFiles/cmTC_f02c1.dir/build.make:65: recipe for target 'CMakeFiles/cmTC_f02c1.dir/CheckSymbolExists.c.o' failed
make[2]: *** [CMakeFiles/cmTC_f02c1.dir/CheckSymbolExists.c.o] Error 1
make[2]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_f02c1/fast' failed
make[1]: *** [cmTC_f02c1/fast] Error 2
make[1]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'

File /home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
/* */
#include <pthread.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef pthread_setname_np
  return ((int*)(&pthread_setname_np))[argc];
#else
  (void)argc;
  return 0;
#endif
}

Determining if the pthread_create exist failed with the following output:
Change Dir: /home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_86d33/fast"
make[1]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_86d33.dir/build.make CMakeFiles/cmTC_86d33.dir/build
make[2]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_86d33.dir/CheckSymbolExists.c.o
/home/buildroot/autobuild/instance-0/output-1/host/bin/arm-buildroot-linux-gnueabihf-gcc --sysroot=/home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabihf/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DNDEBUG -fPIE   -o CMakeFiles/cmTC_86d33.dir/CheckSymbolExists.c.o   -c /home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c
Linking C executable cmTC_86d33
/home/buildroot/autobuild/instance-0/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_86d33.dir/link.txt --verbose=1
/home/buildroot/autobuild/instance-0/output-1/host/bin/arm-buildroot-linux-gnueabihf-gcc --sysroot=/home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabihf/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DNDEBUG    -rdynamic CMakeFiles/cmTC_86d33.dir/CheckSymbolExists.c.o  -o cmTC_86d33 
/home/buildroot/autobuild/instance-0/output-1/host/lib/gcc/arm-buildroot-linux-gnueabihf/9.2.0/../../../../arm-buildroot-linux-gnueabihf/bin/ld: CMakeFiles/cmTC_86d33.dir/CheckSymbolExists.c.o: in function `main':
CheckSymbolExists.c:(.text.startup+0x1c): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_86d33.dir/build.make:97: recipe for target 'cmTC_86d33' failed
make[2]: *** [cmTC_86d33] Error 1
make[2]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_86d33/fast' failed
make[1]: *** [cmTC_86d33/fast] Error 2
make[1]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'

File /home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/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/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_02dd1/fast"
make[1]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_02dd1.dir/build.make CMakeFiles/cmTC_02dd1.dir/build
make[2]: Entering directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_02dd1.dir/CheckFunctionExists.c.o
/home/buildroot/autobuild/instance-0/output-1/host/bin/arm-buildroot-linux-gnueabihf-gcc --sysroot=/home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabihf/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -DCHECK_FUNCTION_EXISTS=pthread_create  -DNDEBUG -fPIE   -o CMakeFiles/cmTC_02dd1.dir/CheckFunctionExists.c.o   -c /home/buildroot/autobuild/instance-0/output-1/host/share/cmake-3.8/Modules/CheckFunctionExists.c
Linking C executable cmTC_02dd1
/home/buildroot/autobuild/instance-0/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_02dd1.dir/link.txt --verbose=1
/home/buildroot/autobuild/instance-0/output-1/host/bin/arm-buildroot-linux-gnueabihf-gcc --sysroot=/home/buildroot/autobuild/instance-0/output-1/host/arm-buildroot-linux-gnueabihf/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -DCHECK_FUNCTION_EXISTS=pthread_create  -DNDEBUG    -rdynamic CMakeFiles/cmTC_02dd1.dir/CheckFunctionExists.c.o  -o cmTC_02dd1 -lpthreads 
/home/buildroot/autobuild/instance-0/output-1/host/lib/gcc/arm-buildroot-linux-gnueabihf/9.2.0/../../../../arm-buildroot-linux-gnueabihf/bin/ld: cannot find -lpthreads
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_02dd1.dir/build.make:97: recipe for target 'cmTC_02dd1' failed
make[2]: *** [cmTC_02dd1] Error 1
make[2]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_02dd1/fast' failed
make[1]: *** [cmTC_02dd1/fast] Error 2
make[1]: Leaving directory '/home/buildroot/autobuild/instance-0/output-1/build/grpc-1.18.0/CMakeFiles/CMakeTmp'