Handle recursion_limit parsing errors

src/test/ui/recursion_limit/overflow.rs

@@ -0,0 +1,7 @@
+// Test the parse error for an overflowing recursion_limit
+
+#![recursion_limit = "999999999999999999999999"]
+//~^ ERROR `recursion_limit` must be a non-negative integer
+//~| `recursion_limit` is too large
+
+fn main() {}