+/* .what is a character array with one character for each member of .data
+ * The character describes the function of the corresponding .data item:
+ * f - start-class data for regstclass optimization
+ * n - Root of op tree for (?{EVAL}) item
+ * o - Start op for (?{EVAL}) item
+ * p - Pad for (?{EVAL} item
+ * s - swash for unicode-style character class, and the multicharacter
+ * strings resulting from casefolding the single-character entries
+ * in the character class
+ * 20010712 mjd@plover.com
+ * (Remember to update re_dup() and pregfree() if you add any items.)
+ */