Replacing std size_of with core size_of.

This allows byteorder to be used in a no_std context.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 5921bcb..a25bab6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -300,7 +300,7 @@ pub type NativeEndian = BigEndian;
 
 macro_rules! read_num_bytes {
     ($ty:ty, $size:expr, $src:expr, $which:ident) => ({
-        assert!($size == ::std::mem::size_of::<$ty>());
+        assert!($size == ::core::mem::size_of::<$ty>());
         assert!($size <= $src.len());
         let mut data: $ty = 0;
         unsafe {