Performing C SOURCE FILE Test ARCH_X86_64 failed with the following output:
Change Dir: /home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_45366/fast"
make[1]: Entering directory `/home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_45366.dir/build.make CMakeFiles/cmTC_45366.dir/build
make[2]: Entering directory `/home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_45366.dir/src.c.o
/home/buildroot/autobuild/run/instance-2/output-1/host/bin/i686-linux-gcc --sysroot=/home/buildroot/autobuild/run/instance-2/output-1/host/i686-buildroot-linux-uclibc/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -DARCH_X86_64  -DNDEBUG   -o CMakeFiles/cmTC_45366.dir/src.c.o   -c /home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp/src.c
/home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp/src.c:3:2: error: #error not x86_64
 #error not x86_64
  ^~~~~
make[2]: *** [CMakeFiles/cmTC_45366.dir/src.c.o] Error 1
make[2]: Leaving directory `/home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp'
make[1]: *** [cmTC_45366/fast] Error 2
make[1]: Leaving directory `/home/buildroot/autobuild/run/instance-2/output-1/build/fastd-18/CMakeFiles/CMakeTmp'

Source file was:

#ifndef __x86_64__
#error not x86_64
#endif

int main() {return 0;}