--- doc/Makefile.orig	2020-11-29 16:45:43.822813150 +0100
+++ doc/Makefile	2020-11-29 16:45:48.392571961 +0100
@@ -34,13 +34,13 @@
 	@mkdir $@
 
 ../html/%.html: %.sgml header.html | ../html
-	@cd ../html && linuxdoc -B html -s 0 -T $(TOC_LEVEL) -H ../doc/header.html ../doc/$<
+	@-cd ../html && linuxdoc -B html -s 0 -T $(TOC_LEVEL) -H ../doc/header.html ../doc/$<
 
 ../html/doc.%: doc.% | ../html
 	cp $< ../html
 
 ../info/%.info: %.sgml | ../info
-	@cd ../info && linuxdoc -B info ../doc/$<
+	@-cd ../info && linuxdoc -B info ../doc/$<
 
 clean:
 	$(RM) -r ../html ../info