Makefile-based builds can configure Git's internal HTML_PATH by defining
htmldir, which is useful for packagers that put documentation in
different locations. Gentoo, for example, uses version-suffixed
directories like ${prefix}/share/doc/git-2.51 and puts the HTML
documentation in an 'html' subdirectory of the same.
Propagate the same configuration knob to Meson-based builds so that
"git --html-path" on such systems can be configured to output the
correct directory.
Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>