Set `MDBOOK_OUTPUT__HTML__INPUT_404` on linkchecker

diff --git a/src/tools/linkchecker/linkcheck.sh b/src/tools/linkchecker/linkcheck.sh
index bbccc17e494c88325b181dc8ebe3d3ef9e831690..b68053c76befce9a4bd6d70efb4c68cd5bb39087 100755 (executable)
--- a/src/tools/linkchecker/linkcheck.sh
+++ b/src/tools/linkchecker/linkcheck.sh
@@ -34,6 +34,9 @@ then
     exit 1
 fi
 
+# Avoid failure caused by newer mdbook.
+export MDBOOK_OUTPUT__HTML__INPUT_404=""
+
 book_name=""
 # Iterative will avoid cleaning up, so you can quickly run it repeatedly.
 iterative=0