patch 9.0.1930: compiler warnings with clang-17

Problem:  compiler warnings with clang-17
Solution: Fix function prototypes and function pointer

fix: clang compilation warnings with -Wstrict-prototypes

Change fixes this kind of compilation warnings with clang:
```
proto/if_python3.pro:13:20: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
   13 | int python3_version();
      |                    ^
      |                     void
```

closes: #13166

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Dominique Pellé <dominique.pelle@tomtom.com>
diff --git a/src/if_python3.c b/src/if_python3.c
index 9d53caf..a04cca3 100644
--- a/src/if_python3.c
+++ b/src/if_python3.c
@@ -2070,7 +2070,7 @@
 }
 
     int
-python3_version()
+python3_version(void)
 {
 #ifdef USE_LIMITED_API
     return Py_LIMITED_API;