Make runtime function return size_t

It returns sizeof(dirent_t), so I'm not sure why its return type is int.
It's only used once, and that usage immediately casts it to usize.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libstd/sys/unix/fs.rs b/src/libstd/sys/unix/fs.rs
index 8ea8f0c6c77..4b4310a1477 100644
--- a/src/libstd/sys/unix/fs.rs
+++ b/src/libstd/sys/unix/fs.rs
@@ -127,11 +127,11 @@ impl Iterator for ReadDir {
 
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
         extern {
-            fn rust_dirent_t_size() -> c_int;
+            fn rust_dirent_t_size() -> size_t;
         }
 
         let mut buf: Vec<u8> = Vec::with_capacity(unsafe {
-            rust_dirent_t_size() as usize
+            rust_dirent_t_size()
         });
         let ptr = buf.as_mut_ptr() as *mut libc::dirent;