A number of Java tools in the 'make' directory operate using the platform default charset. This is often UTF-8, but platform-dependent. As of JDK-8065704, this was standardized on US-ASCII.

In practice, it's common to assume UTF-8 support, so it makes sense to adjust these tools to explicitly reference StandardCharsets.UTF_8.

(My specific use case: fixuppandoc replaces special characters in Markdown sources like ® with ??. It's inconvenient to have to encode all such characters as HTML entities.)