message: Fix g++-9 wee8 compilation warning -> error.
diff: @@ -19,7 +19,7 @@ pushd $$ROOT/wee8
  rm -rf out/wee8
  # Export compiler configuration.
  -export CXXFLAGS="$${CXXFLAGS-} -Wno-deprecated-copy -Wno-unknown-warning-option"
  +export CXXFLAGS="$${CXXFLAGS-} -Werror=no-sign-compare -Wno-deprecated-copy -Wno-unknown-warning-option"
  if [[ ( `uname` == "Darwin" && $${CXX-} == "" ) || $${CXX-} == *"clang"* ]]; then
  export IS_CLANG=true
  export CC=$${CC:-clang}
  