util: limit error-dialogs to win32

These dialogs only exist on Windows, so let's not even expose a util
function for this on other platforms.

The code is only ever called from Windows specific code anyway.

While we're at it, clean up the name a bit as well.

Reviewed-by: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15485>

src/util/u_debug.c

@@ -75,10 +75,10 @@ _util_debug_message(struct util_debug_callback *cb,
 }
 
 
-void
-debug_disable_error_message_boxes(void)
-{
 #ifdef _WIN32
+void
+debug_disable_win32_error_dialogs(void)
+{
    /* When Windows' error message boxes are disabled for this process (as is
     * typically the case when running tests in an automated fashion) we disable
     * CRT message boxes too.
@@ -97,8 +97,8 @@ debug_disable_error_message_boxes(void)
       _set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
 #endif
    }
-#endif /* _WIN32 */
 }
+#endif /* _WIN32 */
 
 
 #ifdef DEBUG