Ported for running on Linux.
Added many macros, including all accents and symbols.
Also allow reading from standard input (instead of always from a file).
Fix mdoc(7)-escaping of output.
Let conditionally-ignored text (e.g., <code>@ifset</code>) allow for nested conditionals as stipulate in the Texinfo manual.
Paste macro and value bodies into the file as Texinfo stipulates and fix the trailing macro newline to conform as well.