[libxml2] Fix compiler warning in examples

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 1bd24d448af5a383953fdfbc5fc467f93be06894
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Sep 2 17:59:09 2022 +0200

    Fix compiler warning in examples

 doc/examples/parse4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/doc/examples/parse4.c b/doc/examples/parse4.c
index 49191d5b..ae8d332a 100644
--- a/doc/examples/parse4.c
+++ b/doc/examples/parse4.c
@@ -136,7 +136,7 @@ int main(int argc, char **argv) {
     return(0);
 }
 #else /* ! LIBXML_PUSH_ENABLED */
-int main(int argc, char **argv) {
+int main(void) {
     fprintf(stderr, "Library not compiled with push parser support\n");
     return(0);
 }