Compilation error on debug compilation of constexp.l

I case we use `LEX_FLAGS=-d` to compile `constexp.l` we get the error:
```
constexp.l: In member function ‘bool ConstExpressionParser::parse(const char*, int, const QCString&)’:
constexp.l:140:17: error: ‘yyscanner’ was not declared in this scope; did you mean ‘yyscan_t’?
  140 |   yyset_debug(1,yyscanner);
      |                 ^~~~~~~~~
      |                 yyscan_t
make[2]: *** [src/CMakeFiles/doxymain.dir/build.make:455: src/CMakeFiles/doxymain.dir/__/generated_src/constexp.cpp.o] Error 1
```

0 files changed, 0 insertions, 0 deletions