Use OCaml 4.08 Stdlib additions

[kritzcreek]

Followup PR to #1000

Unfortunately I can't replace the last remaining Option function Lib.Option.get with http://caml.inria.fr/pub/docs/manual-ocaml-4.08/libref/Option.html Option.value because it uses a labeled argument. Unless we're in favour of adding that label to every invocation or there is another way of ignoring the label.

[ggreif]

Nice clean-up! The Darwin failure is unrelated (non-deterministic drun: #1086).

[kritzcreek]

I don't think this failure is related to my change at all:

closure-params: [tc] [run] [run-ir] [run-low] [comp] [comp-stub] [valid] [valid-stub] [drun-run] [ic-stub-run]
--- closure-params.drun-run (expected)
+++ closure-params.drun-run (actual)
@@ -1,5 +1,10 @@
 ingress(0) System
+debug.print: 1
+debug.print: 3
 ingress(1) Completed: Canister: Payload: 0x4449444c0000
+debug.print: 6
+debug.print: 10
+debug.print: 15
 debug.print: 1
 debug.print: 3
 debug.print: 6

Sadly the tests actually fail with a different error locally for me:

large-array: [tc] [comp] [valid] [drun-run]
--- large-array.drun-run.ret (expected)
+++ large-array.drun-run.ret (actual)
@@ -0,0 +1 @@
+Return code 101
--- large-array.drun-run (expected)
+++ large-array.drun-run (actual)
@@ -1 +1,3 @@
-ingress(0) System
+thread 'Coordinator' panicked at 'Failed to make a checkpoint @1: Error { code: Internal, description: "Failed to copy page #132735 to /run/user/1000/drun.Kz4MbHZWu2gX/tmp/ic.XXX/src/lib.rs:292:25
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
+thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: "PoisonError { inner: .. }"', src/libcore/result.rs:1165:5

But maybe that's just my VM being too small to run the stress test?

[kritzcreek]

Nice clean-up! The Darwin failure is unrelated (non-deterministic drun: #1086).

Oh I see :) well that's good news

[ggreif]

@kritzcreek I have refreshed this from master but there is still a discrepancy (I don't think this is related).