libxtables: prefix/order - strtoui

This commit also throws out the redundant string_to_number_*.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/extensions/libipt_TTL.c b/extensions/libipt_TTL.c
index e124381..6036161 100644
--- a/extensions/libipt_TTL.c
+++ b/extensions/libipt_TTL.c
@@ -44,7 +44,7 @@
 		exit_error(PARAMETER_PROBLEM,
 				"TTL: unexpected `!'");
 	
-	if (string_to_number(optarg, 0, UINT8_MAX, &value) == -1)
+	if (!xtables_strtoui(optarg, NULL, &value, 0, UINT8_MAX))
 		exit_error(PARAMETER_PROBLEM,
 		           "TTL: Expected value between 0 and 255");