diff --git a/src/libextra/ebml.rs b/src/libextra/ebml.rs
index dd08f23a7a10f..462fd60eb983b 100644
--- a/src/libextra/ebml.rs
+++ b/src/libextra/ebml.rs
@@ -82,11 +82,17 @@ pub mod reader {
     use core::cast::transmute;
     use core::int;
     use core::io;
-    use core::ptr::offset;
     use core::str;
-    use core::unstable::intrinsics::bswap32;
     use core::vec;
 
+    #[cfg(target_arch = "x86")]
+    #[cfg(target_arch = "x86_64")]
+    use core::ptr::offset;
+
+    #[cfg(target_arch = "x86")]
+    #[cfg(target_arch = "x86_64")]
+    use core::unstable::intrinsics::bswap32;
+
     // ebml reading
 
     impl Doc {
diff --git a/src/libstd/libc.rs b/src/libstd/libc.rs
index 3c2ae93b65637..41b78afded1a8 100644
--- a/src/libstd/libc.rs
+++ b/src/libstd/libc.rs
@@ -349,7 +349,6 @@ pub mod types {
                 use libc::types::os::arch::c95::{c_uchar, c_uint, c_ulong, time_t};
                 use libc::types::os::arch::c99::{c_longlong, c_ulonglong};
                 use libc::types::os::arch::posix88::{uid_t, gid_t, ino_t};
-                use libc::types::os::arch::posix88::{uid_t};
 
                 pub type nlink_t = u16;
                 pub type blksize_t = u32;