diff --git a/package/libserial/libserial.mk b/package/libserial/libserial.mk
index c5142c5e8f..d2c928bb3e 100644
--- a/package/libserial/libserial.mk
+++ b/package/libserial/libserial.mk
@@ -10,4 +10,6 @@ LIBSERIAL_INSTALL_STAGING = YES
 LIBSERIAL_LICENSE = GPLv2+
 LIBSERIAL_LICENSE_FILES = COPYING
 
+LIBSERIAL_CONF_ENV = ac_cv_prog_DOCBOOK2PDF=no
+
 $(eval $(autotools-package))