cmake HAVE_UNUSED_BUT_SET_VARIABLE examples

ceph/ceph cmake/modules/BuildDPDK.cmake :87 

check_c_compiler_flag("-Wno-unused-but-set-variable"
    HAVE_UNUSED_BUT_SET_VARIABLE)

ceph/ceph cmake/modules/BuildSPDK.cmake :21 

check_c_compiler_flag("-Wno-unused-but-set-variable"
    HAVE_UNUSED_BUT_SET_VARIABLE)

mysql/mysql-router ext/yassl/CMakeLists.txt :67 

CHECK_CXX_COMPILER_FLAG("-Wno-unused-but-set-variable"
                           HAVE_UNUSED_BUT_SET_VARIABLE)