In the yacc test I see warnings like this:

main.c:4:10: error: implicit declaration of function ‘yyparse’ [-Wimplicit-function-declaration]
    4 |   return yyparse ();
      |          ^~~~~~~

and some for yylex which is declared, but with an empty parameter list
instead of void.

I assume this is because GCC becoming more strict to conform with C23
requirements. I did these tests with GCC 14.1.

I have attached a patch fixing these tests on my system.

Collin