auto merge of #12616 : alexcrichton/rust/size, r=huonw

I've been playing around with code size when linking to libstd recently, and these were some findings I found that really helped code size. I started out by eliminating all I/O implementations from libnative and instead just return an unimplemented error.

In doing so, a `fn main() {}` executable was ~378K before this patch, and about 170K after the patch. These size wins are all pretty minor, but they all seemed pretty reasonable to me. With native I/O not stubbed out, this takes the size of an LTO executable from 675K to 400K.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libnative/io/process.rs b/src/libnative/io/process.rs
index 0b833f47395..6ac1f2b3692 100644
--- a/src/libnative/io/process.rs
+++ b/src/libnative/io/process.rs
@@ -470,7 +470,7 @@ fn spawn_process_os(config: p::ProcessConfig,
                 Err(e) => {
                     assert!(e.kind == io::BrokenPipe ||
                             e.kind == io::EndOfFile,
-                            "unexpected error: {:?}", e);
+                            "unexpected error: {}", e);
                     Ok(SpawnProcessResult {
                         pid: pid,
                         handle: ptr::null()
@@ -744,7 +744,7 @@ fn waitpid(pid: pid_t) -> p::ProcessExit {
 
         let mut status = 0 as c_int;
         match retry(|| unsafe { wait::waitpid(pid, &mut status, 0) }) {
-            -1 => fail!("unknown waitpid error: {:?}", super::last_error()),
+            -1 => fail!("unknown waitpid error: {}", super::last_error()),
             _ => {
                 if imp::WIFEXITED(status) {
                     p::ExitStatus(imp::WEXITSTATUS(status) as int)