Address FIXMEs in extfmt / add issue numbers

src/libcore/str.rs

@@ -20,6 +20,7 @@ export
    push_char,
    concat,
    connect,
+   init_elt,
 
    // Reinterpretation
    as_bytes,
@@ -240,6 +241,16 @@ fn connect(v: [str], sep: str) -> str {
     ret s;
 }
 
+#[doc = "Returns a string of <n_elts> repetitions of <c>, which must be \
+           UTF-8"]
+fn init_elt(n_elts: uint, c: char) -> str {
+  let mut rslt = "";
+  uint::range(0u, n_elts) {|_i|
+      push_char(rslt, c);
+  }
+  rslt
+}
+
 /*
 Section: Adding to and removing from a string
 */