[PATCH v3 08/11] virtio-html.cfg: implement workaround for htlatex regression

A regression in htlatex broke the building of html in new Debian
Trixie systems. The bug has been reported upstream:

  https://tug.org/pipermail/tex4ht/2025q4/003774.html

and the following change is a suggested workaround until the eventual
fix is reaches the texlive (and by implication distro) repos:

  https://svn.gnu.org.ua/viewvc/tex4ht/trunk/lit/tex4ht-html4.tex?r1=1750&r2=1749&pathrev=1750

Signed-off-by: Alex Bennée <[email protected]>
---
 virtio-html.cfg | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virtio-html.cfg b/virtio-html.cfg
index c5b9a94..63bf9af 100644
--- a/virtio-html.cfg
+++ b/virtio-html.cfg
@@ -1,4 +1,5 @@
-\Preamble{html} 
+\Preamble{html}
+\expandafter\providecommand\csname hline:color\endcsname{000}
 \begin{document}
 	\ConfigureMark{chapter}{\HCode{<hr><span class="titlemark">}\thechapter\HCode{</span>}}
 	\ConfigureMark{paragraph}{\HCode{<span class="titlemark">}\theparagraph\HCode{</span>}}
-- 
2.47.3