Determining if the include file io.h exists failed with the following output:
Change Dir: /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/gmake" "cmTC_f2cfb/fast"
gmake[1]: Entering directory `/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp'
/usr/bin/gmake -f CMakeFiles/cmTC_f2cfb.dir/build.make CMakeFiles/cmTC_f2cfb.dir/build
gmake[2]: Entering directory `/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_f2cfb.dir/CheckIncludeFile.c.o
/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/host/bin/riscv64-buildroot-linux-musl-gcc --sysroot=/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/host/riscv64-buildroot-linux-musl/sysroot   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os   -DNDEBUG -fPIE   -o CMakeFiles/cmTC_f2cfb.dir/CheckIncludeFile.c.o   -c /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp/CheckIncludeFile.c
/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp/CheckIncludeFile.c:1:10: fatal error: io.h: No such file or directory
 #include <io.h>
          ^~~~~~
compilation terminated.
gmake[2]: *** [CMakeFiles/cmTC_f2cfb.dir/CheckIncludeFile.c.o] Error 1
gmake[2]: Leaving directory `/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp'
gmake[1]: *** [cmTC_f2cfb/fast] Error 2
gmake[1]: Leaving directory `/usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output/build/cmocka-1.1.5/buildroot-build/CMakeFiles/CMakeTmp'