Don't ignore xmllint errors.
diff --git a/docs/GNUmakefile b/docs/GNUmakefile
index 7d1eeba..abb1460 100644
--- a/docs/GNUmakefile
+++ b/docs/GNUmakefile
@@ -16,7 +16,7 @@
 endef
 
 define  XSLT
-	xmllint --noout --valid $2;					\
+	xmllint --noout --valid $2
 	xsltproc -o $3							\
 		$(shell echo $4						\\
 		| sed -e "s/\([^= ]*\)=\([^= ]*\)/--param \1 \"'\2'\"/g") \