nvram.c: Correct librtas function prototypes

Fix build breakage with GCC 15 (which assumes C23) such that and empty
argument list is treated as zero arguments rather than an arbitrary
number.

src/nvram.c: In function ‘dump_rtas_event_entry’:
src/nvram.c:932:18: error: too many arguments to function ‘parse_rtas_event’; expected 0, have 2
  932 |     rtas_event = parse_rtas_event(data, len);
      |                  ^~~~~~~~~~~~~~~~ ~~~~
src/nvram.c:938:5: error: too many arguments to function ‘rtas_print_event’; expected 0, have 3
  938 |     rtas_print_event(stdout, rtas_event, 0);
      |     ^~~~~~~~~~~~~~~~ ~~~~~~
src/nvram.c:940:5: error: too many arguments to function ‘cleanup_rtas_event’; expected 0, have 1
  940 |     cleanup_rtas_event(rtas_event);
      |     ^~~~~~~~~~~~~~~~~~ ~~~~~~~~~~
In file included from src/vcpustat.c:34:

Signed-off-by: Michal Suchanek <[email protected]>
[tyreld: add description to commit log]
Signed-off-by: Tyrel Datwyler <[email protected]>

Author: hramrach

src/nvram.c

@@ -886,6 +886,8 @@ dump_errlog(struct nvram *nvram)
     return 0;
 }
 
+struct rtas_event;
+
 /**
  * dump_rtas_event_entry
  * @brief Dump event-scan data.
@@ -901,11 +903,11 @@ dump_errlog(struct nvram *nvram)
 int
 dump_rtas_event_entry(char *data, int len)
 {
-    void *rtas_event;
+    struct rtas_event *rtas_event;
     void *handle;
-    void *(*parse_rtas_event)();
-    void (*rtas_print_event)();
-    void (*cleanup_rtas_event)();
+    struct rtas_event *(*parse_rtas_event)(char *, int);
+    int (*rtas_print_event)(FILE *, struct rtas_event *, int);
+    int (*cleanup_rtas_event)(struct rtas_event *);
 
     handle = dlopen("/usr/lib/librtasevent.so", RTLD_LAZY);
     if (handle == NULL)