Noteworthy changes in release 2.6.9 (2026-11-11) [stable]

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• Four names that programs used with flex 2.6.4, and that flex 2.6.5
  changed, work again. The global debug flag is again called
  yy_flex_debug (with a prefix, the prefix followed by _flex_debug),
  so a program that declares it with its own extern declaration links
  again; in a C++ scanner it is again the yy_flex_debug member of
  yyFlexLexer. The buffer structure's member that records whether the
  scanner is at the beginning of a line is again called yy_at_bol. A
  definition of YY_READ_BUF_SIZE in the scanner file is used again.
  Defining FLEXINT_H again keeps the scanner from declaring its own
  integer types, for a program that supplies them. The new names
  yyflexdebug and yyatbol() continue to work.

• A generated scanner compiles again in a program that declares
  YY_BUFFER_STATE itself, guarded by YY_TYPEDEF_YY_BUFFER_STATE, as it
  did with flex 2.6.4. Flex 2.6.5 declared its new yybuffer type under
  that same guard, so such a program got no yybuffer and the scanner
  failed to compile. The two types now have separate guards. (#848)

  Thanks to Patrik Obrist.