lib: Add a user data pointer to the argument parsing functions

It can be useful to have one of those to carry state between the handler
parsing the options and the rest of the test. Right now the only thing
we can do is to use global variables for that.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

tests/kms_setmode.c

@@ -662,7 +662,7 @@ static void run_test(const struct test_config *tconf)
 		test_combinations(tconf, connector_num);
 }
 
-static int opt_handler(int opt, int opt_index)
+static int opt_handler(int opt, int opt_index, void *data)
 {
 	switch (opt) {
 	case 'd':
@@ -700,7 +700,7 @@ int main(int argc, char **argv)
 	int ret;
 
 	ret = igt_subtest_init_parse_opts(&argc, argv, "dt:", NULL, help_str,
-					  opt_handler);
+					  opt_handler, NULL);
 	if (ret < 0)
 		return ret == -1 ? 0 : ret;