Creating the API Reference in the (new) `reference' sub-directory is
consistent with other documentation sub-topics, such as `design',
`glyphs' and `tutorial'.
This patch fixes broken hyperlinks in the documentation pointing to
and from the API Reference. It also allows web assets to load from
their relative paths.
* builds/freetype.mk (DOC_DIR): Adjust.
(refdoc, refdoc-venv): Add `--site' argument.
* builds/toplevel.mk (do-dist): Updated.
496601e504