Added prototype of yylex() function

Required for building with the new gcc-14

Signed-off-by: ormorph <roma251078@mail.ru>

sipgen/parser.y

@@ -30,7 +30,7 @@ void yyerror(char* s);
 
 #define inMainModule()      (currentSpec->module == currentModule || currentModule->container != NULL)
 
-
+int yylex();
 static sipSpec *currentSpec;            /* The current spec being parsed. */
 static stringList *neededQualifiers;    /* The list of required qualifiers. */
 static stringList *excludedQualifiers;  /* The list of excluded qualifiers. */