+/* If this bit is set, succeed as soon as we match the whole pattern,
+ without further backtracking. */
+#define RE_NO_POSIX_BACKTRACKING (RE_NO_EMPTY_RANGES << 1)
+
+/* If this bit is set, then (?:...) is treated as a shy group. */
+#define RE_SHY_GROUPS (RE_NO_POSIX_BACKTRACKING << 1)
+