std: Push Child's exit status to sys::process

On Unix we have to be careful to not call `waitpid` twice, but we don't have to
be careful on Windows due to the way process handles work there. As a result the
cached `Option<ExitStatus>` is only necessary on Unix, and it's also just an
implementation detail of the Unix module.

At the same time. also update some code in `kill` on Unix to avoid a wonky
waitpid with WNOHANG. This was added in 0e190b9a to solve #13124, but the
`signal(0)` method is not supported any more so there's no need to for this
workaround. I believe that this is no longer necessary as it's not really doing
anything.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index 6a04aa2f2c4..e5e4187d228 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -202,8 +202,10 @@ impl Process {
         Ok(Process { handle: Handle::new(pi.hProcess) })
     }
 
-    pub unsafe fn kill(&self) -> io::Result<()> {
-        try!(cvt(c::TerminateProcess(self.handle.raw(), 1)));
+    pub fn kill(&mut self) -> io::Result<()> {
+        try!(cvt(unsafe {
+            c::TerminateProcess(self.handle.raw(), 1)
+        }));
         Ok(())
     }
 
@@ -213,7 +215,7 @@ impl Process {
         }
     }
 
-    pub fn wait(&self) -> io::Result<ExitStatus> {
+    pub fn wait(&mut self) -> io::Result<ExitStatus> {
         unsafe {
             let res = c::WaitForSingleObject(self.handle.raw(), c::INFINITE);
             if res != c::WAIT_OBJECT_0 {