message: tools: fix snake_case_to_camel_case for macOS
  The problem is that BSD (non GNU) sed on macOS does not support case
  conversions. Hence we need to implement the snake_case to camelCase
  conversion in awk.
diff: @@ -11,7 +11,7 @@ protoc_binary="${third_party_dir}/install/bin/protoc"
  protoc_grpc_binary="${third_party_dir}/install/bin/grpc_cpp_plugin"
  function snake_case_to_camel_case {
  - echo $1 | sed -r 's/(^|_)([a-z])/\U\2/g'
  + echo $1 | awk -v FS="_" -v OFS="" '{for (i=1;i<=NF;i++) $i=toupper(substr($i,1,1)) substr($i,2)} 1'
  }
  command -v ${protoc_binary} > /dev/null && command -v ${protoc_grpc_binary} > /dev/null || {
  