join: "support" field numbers larger than usize::MAX

They silently get folded to usize::MAX, which is the official GNU behavior.

tests/by-util/test_join.rs

@@ -75,6 +75,27 @@ fn different_field() {
         .stdout_only_fixture("different_field.expected");
 }
 
+#[test]
+fn out_of_bounds_fields() {
+    new_ucmd!()
+        .arg("fields_1.txt")
+        .arg("fields_4.txt")
+        .arg("-1")
+        .arg("3")
+        .arg("-2")
+        .arg("5")
+        .succeeds()
+        .stdout_only_fixture("out_of_bounds_fields.expected");
+
+    new_ucmd!()
+        .arg("fields_1.txt")
+        .arg("fields_4.txt")
+        .arg("-j")
+        .arg("100000000000000000000") // > usize::MAX for 64 bits
+        .succeeds()
+        .stdout_only_fixture("out_of_bounds_fields.expected");
+}
+
 #[test]
 fn unpaired_lines() {
     new_ucmd!()

tests/fixtures/join/out_of_bounds_fields.expected

@@ -0,0 +1,25 @@
+ 1 2 c 1 cd
+ 1 3 d 2 de
+ 1 5 e 3 ef
+ 1 7 f 4 fg
+ 1 11 g 5 gh
+ 2 2 c 1 cd
+ 2 3 d 2 de
+ 2 5 e 3 ef
+ 2 7 f 4 fg
+ 2 11 g 5 gh
+ 3 2 c 1 cd
+ 3 3 d 2 de
+ 3 5 e 3 ef
+ 3 7 f 4 fg
+ 3 11 g 5 gh
+ 5 2 c 1 cd
+ 5 3 d 2 de
+ 5 5 e 3 ef
+ 5 7 f 4 fg
+ 5 11 g 5 gh
+ 8 2 c 1 cd
+ 8 3 d 2 de
+ 8 5 e 3 ef
+ 8 7 f 4 fg
+ 8 11 g 5 gh