+/* For most options, 0 means no limits, but with -p in the picture, that causes
+ a problem on the maximum recursion depth variable. To retain backwards
+ compatibility we allow users to consider "0" to be synonymous with "inf" for
+ -l, but internally infinite recursion is specified by -1 and 0 means to only
+ retrieve the requisites of a single document. */
+#define INFINITE_RECURSION -1
+