Declare main() with argc/argv params in tests

Declaring the main method as "int main(void)" causes issues with SDL.

Fixes #1209 <https://github.com/Genymobile/scrcpy/issues/1209>

app/tests/test_cbuf.c

@@ -65,7 +65,10 @@ static void test_cbuf_push_take(void) {
     assert(item == 35);
 }
 
-int main(void) {
+int main(int argc, char *argv[]) {
+    (void) argc;
+    (void) argv;
+
     test_cbuf_empty();
     test_cbuf_full();
     test_cbuf_push_take();