Whitelist improper ctypes to support old rustc versions

diff --git a/src/cargo/util/sha256.rs b/src/cargo/util/sha256.rs
index 04e1974210fe64f94ce762c8ddfad5d016bc15f2..3a6dc5055b75e583a73c054cebd517d0cfbf2713 100644 (file)
--- a/src/cargo/util/sha256.rs
+++ b/src/cargo/util/sha256.rs
@@ -3,7 +3,8 @@ pub use self::imp::Sha256;
 // Someone upstream will link to OpenSSL, so we don't need to explicitly
 // link to it ourselves. Hence we pick up Sha256 digests from OpenSSL
 #[cfg(not(windows))]
-#[allow(bad_style)]
+// allow improper ctypes because size_t falls under that in old compilers
+#[allow(bad_style, improper_ctypes)]
 mod imp {
     use libc;