Merge #598

598: Hello world r=philberty a=philberty

```rust
extern "C" {
    fn puts(s: *const i8);
}

fn main() {
    unsafe {
        let a = "Hello World\0";
        let b = a as *const str;
        let c = b as *const i8;
        puts(c);
    }
}
```

Fixes #421

Co-authored-by: Philip Herron <philip.herron@embecosm.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-item.h b/gcc/rust/backend/rust-compile-item.h
index eacfda9..a6bc7f3 100644
--- a/gcc/rust/backend/rust-compile-item.h
+++ b/gcc/rust/backend/rust-compile-item.h
@@ -26,6 +26,7 @@
 #include "rust-compile-stmt.h"
 #include "rust-compile-expr.h"
 #include "rust-compile-fnparam.h"
+#include "rust-compile-extern.h"
 
 namespace Rust {
 namespace Compile {
@@ -274,6 +275,14 @@ public:
 					compile_fns);
   }
 
+  void visit (HIR::ExternBlock &extern_block) override
+  {
+    for (auto &item : extern_block.get_extern_items ())
+      {
+	CompileExternItem::compile (item.get (), ctx, compile_fns, concrete);
+      }
+  }
+
 private:
   CompileItem (Context *ctx, bool compile_fns, TyTy::BaseType *concrete)
     : HIRCompileBase (ctx), compile_fns (compile_fns), concrete (concrete)