fix uucore::fs for windows

- standardize the return value of `std::env::current_dir()` by using `canonicalize()`

.# [why]

`std::env::current_dir()` will, in some situations on windows hosts, return
"short"-type paths (eg, "C:\Progra~1\..."). Using `canonicalize()` transforms
the path in a standard long form but may also require removing a leading
"\\?\" prefix.

src/uucore/Cargo.toml

@@ -16,6 +16,7 @@ travis-ci = { repository = "uutils/uucore" }
 appveyor = { repository = "uutils/uucore" }
 
 [dependencies]
+dunce = "1.0.0"
 getopts = "0.2.18"
 failure = { version = "0.1.1", optional = true }
 failure_derive = { version = "0.1.1", optional = true }
@@ -43,4 +44,3 @@ entries = ["libc"]
 zero-copy = ["nix", "libc", "lazy_static", "platform-info"]
 wide = []
 default = []
-

src/uucore/src/fs.rs

@@ -6,6 +6,8 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
+#[cfg(windows)]
+extern crate dunce;
 #[cfg(target_os = "redox")]
 extern crate termion;
 
@@ -101,7 +103,7 @@ pub fn canonicalize<P: AsRef<Path>>(original: P, can_mode: CanonicalizeMode) ->
     let original = if original.is_absolute() {
         original.to_path_buf()
     } else {
-        env::current_dir().unwrap().join(original)
+        dunce::canonicalize(env::current_dir().unwrap()).unwrap().join(original)
     };
 
     let mut result = PathBuf::new();