Enable std-trait workaround for windows/unix targets

From `v0.1.0` to `v0.1.6` we had this enabled for windows/unix, and we
inadvertantly removed it.

Signed-off-by: Joe Richey <joerichey@google.com>

Author: josephlr

src/lib.rs

@@ -164,12 +164,15 @@ mod util;
 // for some platforms, even if they don't enable the "std" feature.
 #[cfg(any(
     feature = "std",
+    windows,
     target_os = "android",
     target_os = "dragonfly",
     target_os = "emscripten",
     target_os = "freebsd",
+    target_os = "fuchsia",
     target_os = "haiku",
     target_os = "illumos",
+    target_os = "ios",
     target_os = "linux",
     target_os = "macos",
     target_os = "netbsd",