configure options to control availability of external filters in xorriso

libisoburn/trunk/xorriso/README

@@ -92,6 +92,14 @@ Other deliberate dependency reduction options of ./configure are:
     --disable-libacl   avoid use of ACL functions like acl_to_text()
     --disable-xattr    avoid use of xattr functions like listxattr()
 
+xorriso allows to use external processes as file content filters. This is
+a potential security risk which may be avoided by ./configure option
+    --disable-external-filters
+
+By default the filter feature is disabled if effective user id and real
+user id differ. This ban can be lifted by
+    --enable-external-filters-setuid
+
 If you want xorriso to report a "Build timestamp" with its option -version:
     make buildstamped