Make tests build on CloudABI.

There are some tests that need to be disabled on CloudABI specifically,
due to the fact that the shims cannot be built in combination with
unix::ext or windows::ext. Also improve the scoping of some imports to
suppress compiler warnings.

src/libstd/env.rs

@@ -956,8 +956,7 @@ mod arch {
 mod tests {
     use super::*;
 
-    use ffi::OsStr;
-    use path::{Path, PathBuf};
+    use path::Path;
 
     #[test]
     #[cfg_attr(target_os = "emscripten", ignore)]
@@ -980,6 +979,8 @@ mod tests {
     #[test]
     #[cfg(windows)]
     fn split_paths_windows() {
+        use path::PathBuf;
+
         fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
             split_paths(unparsed).collect::<Vec<_>>() ==
                 parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
@@ -1000,6 +1001,8 @@ mod tests {
     #[test]
     #[cfg(unix)]
     fn split_paths_unix() {
+        use path::PathBuf;
+
         fn check_parse(unparsed: &str, parsed: &[&str]) -> bool {
             split_paths(unparsed).collect::<Vec<_>>() ==
                 parsed.iter().map(|s| PathBuf::from(*s)).collect::<Vec<_>>()
@@ -1015,6 +1018,8 @@ mod tests {
     #[test]
     #[cfg(unix)]
     fn join_paths_unix() {
+        use ffi::OsStr;
+
         fn test_eq(input: &[&str], output: &str) -> bool {
             &*join_paths(input.iter().cloned()).unwrap() ==
                 OsStr::new(output)
@@ -1031,6 +1036,8 @@ mod tests {
     #[test]
     #[cfg(windows)]
     fn join_paths_windows() {
+        use ffi::OsStr;
+
         fn test_eq(input: &[&str], output: &str) -> bool {
             &*join_paths(input.iter().cloned()).unwrap() ==
                 OsStr::new(output)

src/libstd/fs.rs

@@ -1981,7 +1981,7 @@ impl AsInnerMut<fs_imp::DirBuilder> for DirBuilder {
     }
 }
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "cloudabi", target_os = "emscripten"))))]
 mod tests {
     use io::prelude::*;
 

src/libstd/net/tcp.rs

@@ -885,7 +885,7 @@ impl fmt::Debug for TcpListener {
     }
 }
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "cloudabi", target_os = "emscripten"))))]
 mod tests {
     use io::ErrorKind;
     use io::prelude::*;

src/libstd/net/udp.rs

@@ -786,7 +786,7 @@ impl fmt::Debug for UdpSocket {
     }
 }
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "cloudabi", target_os = "emscripten"))))]
 mod tests {
     use io::ErrorKind;
     use net::*;

src/libstd/process.rs

@@ -1392,7 +1392,7 @@ pub fn id() -> u32 {
     ::sys::os::getpid()
 }
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "cloudabi", target_os = "emscripten"))))]
 mod tests {
     use io::prelude::*;