auto merge of #10064 : luqmana/rust/vvv, r=nikomatsakis

Fixes #2057.

Example:
```Rust
#[no_std];

type c_char = u8;
type c_int = i32;
type size_t = uint;

extern {
    fn printf(format: *c_char, ...) -> c_int;
}

#[lang="fail_bounds_check"]
fn fail_bounds_check(_: *c_char, _: size_t, _: size_t, _: size_t) {}

#[start]
#[fixed_stack_segment]
fn main(_: int, _: **u8) -> int {
    unsafe {
        let msg = bytes!("Hello World!

3 files changed, 25 insertions, 0 deletions

diff --git a/src/libstd/reflect.rs b/src/libstd/reflect.rs
index 19fa9abc0da..c841750d7ce 100644
--- a/src/libstd/reflect.rs
+++ b/src/libstd/reflect.rs
@@ -382,11 +382,18 @@ impl<V:TyVisitor + MovePtr> TyVisitor for MovePtrAdaptor<V> {
         true
     }
 
+    #[cfg(stage0)]
     fn visit_fn_output(&mut self, retstyle: uint, inner: *TyDesc) -> bool {
         if ! self.inner.visit_fn_output(retstyle, inner) { return false; }
         true
     }
 
+    #[cfg(not(stage0))]
+    fn visit_fn_output(&mut self, retstyle: uint, variadic: bool, inner: *TyDesc) -> bool {
+        if ! self.inner.visit_fn_output(retstyle, variadic, inner) { return false; }
+        true
+    }
+
     fn visit_leave_fn(&mut self, purity: uint, proto: uint,
                       n_inputs: uint, retstyle: uint) -> bool {
         if ! self.inner.visit_leave_fn(purity, proto, n_inputs, retstyle) {
diff --git a/src/libstd/repr.rs b/src/libstd/repr.rs
index dd68c57e37e..97b42a1ebc1 100644
--- a/src/libstd/repr.rs
+++ b/src/libstd/repr.rs
@@ -572,6 +572,7 @@ impl<'self> TyVisitor for ReprVisitor<'self> {
         true
     }
 
+    #[cfg(stage0)]
     fn visit_fn_output(&mut self, _retstyle: uint, inner: *TyDesc) -> bool {
         self.writer.write(")".as_bytes());
         let name = unsafe { (*inner).name };
@@ -582,6 +583,20 @@ impl<'self> TyVisitor for ReprVisitor<'self> {
         true
     }
 
+    #[cfg(not(stage0))]
+    fn visit_fn_output(&mut self, _retstyle: uint, variadic: bool, inner: *TyDesc) -> bool {
+        if variadic {
+            self.writer.write(", ...".as_bytes());
+        }
+        self.writer.write(")".as_bytes());
+        let name = unsafe { (*inner).name };
+        if name != "()" {
+            self.writer.write(" -> ".as_bytes());
+            self.writer.write(name.as_bytes());
+        }
+        true
+    }
+
     fn visit_leave_fn(&mut self, _purity: uint, _proto: uint,
                       _n_inputs: uint, _retstyle: uint) -> bool { true }
 
diff --git a/src/libstd/unstable/intrinsics.rs b/src/libstd/unstable/intrinsics.rs
index d042440b4f3..404ed85985c 100644
--- a/src/libstd/unstable/intrinsics.rs
+++ b/src/libstd/unstable/intrinsics.rs
@@ -160,7 +160,10 @@ pub trait TyVisitor {
     fn visit_enter_fn(&mut self, purity: uint, proto: uint,
                       n_inputs: uint, retstyle: uint) -> bool;
     fn visit_fn_input(&mut self, i: uint, mode: uint, inner: *TyDesc) -> bool;
+    #[cfg(stage0)]
     fn visit_fn_output(&mut self, retstyle: uint, inner: *TyDesc) -> bool;
+    #[cfg(not(stage0))]
+    fn visit_fn_output(&mut self, retstyle: uint, variadic: bool, inner: *TyDesc) -> bool;
     fn visit_leave_fn(&mut self, purity: uint, proto: uint,
                       n_inputs: uint, retstyle: uint) -> bool;