Test fixes from the rollup

Closes #15807 (Deprecate some unsafe functions in `str::raw` and remove `OwnedStr` trait)
Closes #15859 (Implement `Show` for `CString` and fix warning compiling tests for libcollections)
Closes #15911 (Updated LLVM for iOS)
Closes #15925 (libsyntax: Remove `~self` and `mut ~self` from the language.)
Closes #15930 (Add examples for Checked[Add|Sub|Mul|Div])
Closes #15933 (rustdoc: make table of contents optional)
Closes #15937 (librustc: Make bare functions implement the `FnMut` trait.)
Closes #15938 (librustc: Check structure constructors against their types.)
Closes #15939 (rustdoc: Add a --crate-name option)
Closes #15942 (Document trie collections)
Closes #15943 (Document SmallIntMap)

src/libnative/io/addrinfo.rs

@@ -27,7 +27,9 @@ impl GetAddrInfoRequest {
         assert!(host.is_some() || servname.is_some());
 
         let c_host = host.map(|x| x.to_c_str());
+        let c_host = c_host.as_ref().map(|x| x.as_ptr()).unwrap_or(null());
         let c_serv = servname.map(|x| x.to_c_str());
+        let c_serv = c_serv.as_ref().map(|x| x.as_ptr()).unwrap_or(null());
 
         let hint = hint.map(|hint| {
             libc::addrinfo {
@@ -49,9 +51,7 @@ impl GetAddrInfoRequest {
 
         // Make the call
         let s = unsafe {
-            let ch = if c_host.is_none() { null() } else { c_host.unwrap().as_ptr() };
-            let cs = if c_serv.is_none() { null() } else { c_serv.unwrap().as_ptr() };
-            getaddrinfo(ch, cs, hint_ptr, &mut res)
+            getaddrinfo(c_host, c_serv, hint_ptr, &mut res)
         };
 
         // Error?