+/* If this bit is set, succeed as soon as we match the whole pattern,
+ without further backtracking. */
+#define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
+
+/* If this bit is set, do not process the GNU regex operators.
+ If not set, then the GNU regex operators are recognized. */
+#define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
+
+/* If this bit is set, then *?, +? and ?? match non greedily. */
+#define RE_FRUGAL (RE_NO_GNU_OPS << 1)
+
+/* If this bit is set, then (?:...) is treated as a shy group. */
+#define RE_SHY_GROUPS (RE_FRUGAL << 1)
+
+/* If this bit is set, ^ and $ only match at beg/end of buffer. */
+#define RE_NO_NEWLINE_ANCHOR (RE_SHY_GROUPS << 1)
+
+/* If this bit is set, turn on internal regex debugging.
+ If not set, and debugging was on, turn it off.
+ This only works if regex.c is compiled -DDEBUG.
+ We define this bit always, so that all that's needed to turn on
+ debugging is to recompile regex.c; the calling code can always have
+ this bit set, and it won't affect anything in the normal case. */
+#define RE_DEBUG (RE_NO_NEWLINE_ANCHOR << 1)
+