Comment # 1 on bug 1221682 from David Disseldorp

Thanks for the report...

(In reply to Michal Jireš from comment #0)
> Building autofs with GCC 14 fails here:
> https://build.opensuse.org/package/live_build_log/openSUSE:Factory:Staging:
> Gcc7/autofs/standard/x86_64
> 
> Due to (exhaustive list of errors):
> 
> cyrus-sasl.c:112:25: error: initialization of ‘int (*)(void)’ from
> incompatible pointer type ‘int (*)(void *, int,  const char **, unsigned int
> *)’ [-Wincompatible-pointer-types]
>   112 |         { SASL_CB_USER, &getuser_func, NULL },
...

This appears to be due to the somewhat confusing sasl_callback_t interface
provided via cyrus-sasl's sasl.h:

 350 /*
 351  * Extensible type for a client/server callbacks
 352  *  id      -- identifies callback type
 353  *  proc    -- procedure call arguments vary based on id
 354  *  context -- context passed to procedure
 355  */
 356 /* Note that any memory that is allocated by the callback needs to be
 357  * freed by the application, be it via function call or interaction.
 358  *
 359  * It may be freed after sasl_*_step returns SASL_OK.  if the mechanism
 360  * requires this information to persist (for a security layer, for
example)
 361  * it must maintain a private copy.
 362  */
 363 typedef struct sasl_callback {
 364     /* Identifies the type of the callback function.
 365      * Mechanisms must ignore callbacks with id's they don't recognize.
 366      */
 367     unsigned long id;
 368     int (*proc)(void);   /* Callback function.  Types of arguments vary by
'id' */
 369     void *context;
 370 } sasl_callback_t;

So the @proc function pointer's arguments are *supposed* to vary based on id,
but it's declared parameter list is (void).
I wonder whether the sasl_callback_t.proc entry could get away with an unnamed
union covering all argument cases for a valid @id?