test suite now also passes on MIR-libstd

Also enable some tests that were disabled for no apparant reason.
(The comment in zst.rs was wrong, the test was disabled also for miri execution.)
Delete env_args test as the args can actually be queried with MIR-libstd (currently, they are always empty)

src/step.rs

@@ -34,7 +34,7 @@ pub fn step(&mut self) -> EvalResult<'tcx, bool> {
         if self.stack.is_empty() {
             if let Some((instance, ptr)) = self.memory.fetch_tls_dtor() {
                 trace!("Running TLS dtor {:?} on {:?}", instance, ptr);
-                // TODO: Potientiually, this has to support all the other possible instances? See eval_fn_call in terminator/mod.rs
+                // TODO: Potientially, this has to support all the other possible instances? See eval_fn_call in terminator/mod.rs
                 let mir = self.load_mir(instance.def)?;
                 self.push_stack_frame(
                     instance,

src/terminator/mod.rs

@@ -622,6 +622,10 @@ fn call_c_abi(
                 return Ok(());
             }
 
+            "__rust_start_panic" => {
+                return Err(EvalError::Panic);
+            }
+
             "memcmp" => {
                 let left = args[0].read_ptr(&self.memory)?;
                 let right = args[1].read_ptr(&self.memory)?;

tests/compile-fail/env_args.rs

-fn main() {
-    let x = std::env::args(); //~ ERROR miri does not support program arguments
-    assert_eq!(x.count(), 1);
-}

tests/compile-fail/oom.rs

 #![feature(custom_attribute, attr_literals)]
-#![miri(memory_size=20)]
+#![miri(memory_size=4095)]
 
 fn main() {
-    let _x = [42; 10];
-    //~^ERROR tried to allocate 40 more bytes, but only
+    let _x = [42; 1024];
+    //~^ERROR tried to allocate 4096 more bytes, but only
 }

tests/compile-fail/oom2.rs

 #![feature(box_syntax, custom_attribute, attr_literals)]
-#![miri(memory_size=1000)]
+#![miri(memory_size=2048)]
 
 fn main() {
     loop {

tests/compile-fail/stack_limit.rs

 #![feature(custom_attribute, attr_literals)]
-#![miri(stack_limit=2)]
+#![miri(stack_limit=16)]
 
 fn bar() {
     foo();
@@ -10,10 +10,16 @@ fn foo() {
 }
 
 fn cake() {
-    flubber();
+    flubber(3);
 }
 
-fn flubber() {}
+fn flubber(i: u32) {
+    if i > 0 {
+        flubber(i-1);
+    } else {
+        bar();
+    }
+}
 
 fn main() {
     bar();

tests/run-pass/aux_test.rs

 // aux-build:dep.rs
-// ignore-cross-compile
 
 extern crate dep;
 

tests/run-pass/hello.rs

+fn main() {
+    println!("Hello, world!");
+}

tests/run-pass/zst.rs

-// the following flag prevents this test from running on the host machine
-// this should only be run on miri, because rust doesn't (yet?) optimize ZSTs of different types
-// into the same memory location
-// ignore-test
-
-
 #[derive(PartialEq, Debug)]
 struct A;