Migrate import statements and macros to Rust 2018.

fuzz/Cargo.toml

@@ -13,11 +13,9 @@ libfuzzer-sys = { version = "0.3"}
 arrayref = "0.3.6"
 libtock_drivers = { path = "../third_party/libtock-drivers" }
 crypto = { path = "../libraries/crypto", features = ['std'] }
-cbor = { path = "../libraries/cbor" }
-
-[dependencies.ctap2]
-path = ".."
-features = ['std', 'ram_storage']
+cbor = { path = "../libraries/cbor", features = ['std'] }
+ctap2 = { path = "..", features = ['std', 'ram_storage'] }
+lang_items = { path = "../third_party/lang-items", features = ['std'] }
 
 # Prevent this from interfering with workspaces
 [workspace]