cmake HAVE_WNO_UNUSED_RESULT examples

oscarlab/betrfs portability/tests/CMakeLists.txt :21 

check_c_compiler_flag(-Wno-unused-result HAVE_WNO_UNUSED_RESULT)

alibaba/AliSQL storage/tokudb/ft-index/portability/tests/CMakeLists.txt :21 

check_c_compiler_flag(-Wno-unused-result HAVE_WNO_UNUSED_RESULT)

percona/PerconaFT portability/tests/CMakeLists.txt :21 

check_c_compiler_flag(-Wno-unused-result HAVE_WNO_UNUSED_RESULT)