Performing C++ SOURCE FILE Test HAVE_CXX_ATOMICS64_WITHOUT_LIB failed with the following output:
Change Dir: /srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_60699/fast"
make[1]: Entering directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_60699.dir/build.make CMakeFiles/cmTC_60699.dir/build
make[2]: Entering directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_60699.dir/src.cxx.o
/srv/storage/autobuild/run/instance-1/output-1/host/bin/nios2-linux-gnu-g++ --sysroot=/srv/storage/autobuild/run/instance-1/output-1/host/nios2-buildroot-linux-gnu/sysroot    -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g2 -D_FORTIFY_SOURCE=1 -Wall -Wconversion -pedantic -Wextra -Wno-missing-field-initializers -DHAVE_CXX_ATOMICS64_WITHOUT_LIB -std=c++11   -o CMakeFiles/cmTC_60699.dir/src.cxx.o -c /srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp/src.cxx
/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp/src.cxx: In function 'int main()':
/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp/src.cxx:6:12: warning: unused variable 'i' [-Wunused-variable]
   uint64_t i = x.load(std::memory_order_relaxed);
            ^
Linking CXX executable cmTC_60699
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_60699.dir/link.txt --verbose=1
/srv/storage/autobuild/run/instance-1/output-1/host/bin/nios2-linux-gnu-g++ --sysroot=/srv/storage/autobuild/run/instance-1/output-1/host/nios2-buildroot-linux-gnu/sysroot  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g2 -D_FORTIFY_SOURCE=1 -Wall -Wconversion -pedantic -Wextra -Wno-missing-field-initializers -DHAVE_CXX_ATOMICS64_WITHOUT_LIB -std=c++11    CMakeFiles/cmTC_60699.dir/src.cxx.o  -o cmTC_60699 
CMakeFiles/cmTC_60699.dir/src.cxx.o: In function `std::__atomic_base<unsigned long long>::load(std::memory_order) const':
/srv/storage/autobuild/run/instance-1/output-1/host/opt/ext-toolchain/nios2-linux-gnu/include/c++/7.3.1/bits/atomic_base.h:396: undefined reference to `__atomic_load_8'
/srv/storage/autobuild/run/instance-1/output-1/host/opt/ext-toolchain/nios2-linux-gnu/include/c++/7.3.1/bits/atomic_base.h:396: undefined reference to `__atomic_load_8'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/cmTC_60699.dir/build.make:87: cmTC_60699] Error 1
make[2]: Leaving directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'
make[1]: *** [Makefile:121: cmTC_60699/fast] Error 2
make[1]: Leaving directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'

Source file was:

#include <atomic>
#include <cstdint>
std::atomic<uint64_t> x (0);
int main() {
  uint64_t i = x.load(std::memory_order_relaxed);
  return 0;
}

Determining if the pthread_create exist failed with the following output:
Change Dir: /srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_a86f9/fast"
make[1]: Entering directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_a86f9.dir/build.make CMakeFiles/cmTC_a86f9.dir/build
make[2]: Entering directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_a86f9.dir/CheckSymbolExists.c.o
/srv/storage/autobuild/run/instance-1/output-1/host/bin/nios2-linux-gnu-gcc --sysroot=/srv/storage/autobuild/run/instance-1/output-1/host/nios2-buildroot-linux-gnu/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g2 -D_FORTIFY_SOURCE=1    -o CMakeFiles/cmTC_a86f9.dir/CheckSymbolExists.c.o   -c /srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp/CheckSymbolExists.c
Linking C executable cmTC_a86f9
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_a86f9.dir/link.txt --verbose=1
/srv/storage/autobuild/run/instance-1/output-1/host/bin/nios2-linux-gnu-gcc --sysroot=/srv/storage/autobuild/run/instance-1/output-1/host/nios2-buildroot-linux-gnu/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -g2 -D_FORTIFY_SOURCE=1     CMakeFiles/cmTC_a86f9.dir/CheckSymbolExists.c.o  -o cmTC_a86f9 -latomic 
/srv/storage/autobuild/run/instance-1/output-1/host/opt/ext-toolchain/bin/../lib/gcc/nios2-linux-gnu/7.3.1/../../../../nios2-linux-gnu/bin/ld: CMakeFiles/cmTC_a86f9.dir/CheckSymbolExists.c.o: undefined reference to symbol 'pthread_create@@GLIBC_2.21'
/srv/storage/autobuild/run/instance-1/output-1/host/nios2-buildroot-linux-gnu/sysroot/lib/libpthread.so.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/cmTC_a86f9.dir/build.make:87: cmTC_a86f9] Error 1
make[2]: Leaving directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'
make[1]: *** [Makefile:121: cmTC_a86f9/fast] Error 2
make[1]: Leaving directory '/srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/CMakeFiles/CMakeTmp'

File /srv/storage/autobuild/run/instance-1/output-1/build/pistache-f2f5a50fbfb5b8ef6cf1d3d2a9d442a8270e375d/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
}