loader, iter: add shim for go1.22 and earlier

loader/goroot.go

@@ -261,6 +261,10 @@ func pathsToOverride(goMinor int, needsSyscallPackage bool) map[string]bool {
 		"unique/":                     false,
 	}
 
+	if goMinor <= 22 {
+		paths["iter]"] = false
+	}
+
 	if goMinor >= 19 {
 		paths["crypto/internal/"] = true
 		paths["crypto/internal/boring/"] = true

src/iter/iter.go

@@ -0,0 +1,17 @@
+//go:build !go1.23
+
+// Delete this file when TinyGo drops support for Go 1.22.
+
+package iter
+
+// Seq is an iterator over sequences of individual values.
+// When called as seq(yield), seq calls yield(v) for each value v in the sequence,
+// stopping early if yield returns false.
+// See the [iter] package documentation for more details.
+type Seq[V any] func(yield func(V) bool)
+
+// Seq2 is an iterator over sequences of pairs of values, most commonly key-value pairs.
+// When called as seq(yield), seq calls yield(k, v) for each pair (k, v) in the sequence,
+// stopping early if yield returns false.
+// See the [iter] package documentation for more details.
+type Seq2[K, V any] func(yield func(K, V) bool)