getting back android traget in case without rustc-dep-of-std

Author: Bryanskiy

src/unix/mod.rs

@@ -357,6 +357,7 @@ cfg_if! {
     } else if #[cfg(any(target_os = "macos",
                         target_os = "ios",
                         target_os = "watchos",
+                        target_os = "android",
                         target_os = "openbsd"))] {
         #[link(name = "c")]
         #[link(name = "m")]