md2html: render linked .md via the about view, fix relative base

Links to markdown files now point at /<repo>/about/<path> (rendered
through the about-filter) instead of /<repo>/tree/<path> (raw blob), so
clicking a README link to another .md shows rendered markdown.

Also resolve relative links against the rendered file's own directory:
about-formatting.sh now forwards the filename cgit passes ($1) to
md2html as argv[1], and md2html uses dirname(argv[1]) as the base. This
makes links *inside* a rendered subpage (docs/foo.md -> ./bar.md,
../README.md, images) resolve correctly. Non-markdown files and
directories still go to tree/; images to plain/; about/ links carry no
?h= since the about view renders against the configured readme ref.

1 files changed, 1 insertions, 1 deletions

diff --git a/filters/about-formatting.sh b/filters/about-formatting.sh
index 85daf9c..c6c4f9c 100755
--- a/filters/about-formatting.sh
+++ b/filters/about-formatting.sh
@@ -19,7 +19,7 @@
 
 cd "$(dirname $0)/html-converters/"
 case "$(printf '%s' "$1" | tr '[:upper:]' '[:lower:]')" in
-	*.markdown|*.mdown|*.md|*.mkd) exec ./md2html; ;;
+	*.markdown|*.mdown|*.md|*.mkd) exec ./md2html "$1"; ;;
 	*.rst) exec ./rst2html; ;;
 	*.[1-9]) exec ./man2html; ;;
 	*.htm|*.html) exec cat; ;;