Allow import of Linux macros in Rust2018

Finish off the work started in 8c9ac5a allowing the use of macros
without needing to import local inner macros.

src/sys/ioctl/linux.rs

@@ -93,7 +93,7 @@ macro_rules! ioc {
 /// ioctl_write_int_bad!(kvm_create_vm, request_code_none!(KVMIO, 0x03));
 /// # fn main() {}
 /// ```
-#[macro_export]
+#[macro_export(local_inner_macros)]
 macro_rules! request_code_none {
     ($ty:expr, $nr:expr) => (ioc!($crate::sys::ioctl::NONE, $ty, $nr, 0))
 }
@@ -108,7 +108,7 @@ macro_rules! request_code_none {
 /// The read/write direction is relative to userland, so this
 /// command would be userland is reading and the kernel is
 /// writing.
-#[macro_export]
+#[macro_export(local_inner_macros)]
 macro_rules! request_code_read {
     ($ty:expr, $nr:expr, $sz:expr) => (ioc!($crate::sys::ioctl::READ, $ty, $nr, $sz))
 }
@@ -123,7 +123,7 @@ macro_rules! request_code_read {
 /// The read/write direction is relative to userland, so this
 /// command would be userland is writing and the kernel is
 /// reading.
-#[macro_export]
+#[macro_export(local_inner_macros)]
 macro_rules! request_code_write {
     ($ty:expr, $nr:expr, $sz:expr) => (ioc!($crate::sys::ioctl::WRITE, $ty, $nr, $sz))
 }
@@ -134,7 +134,7 @@ macro_rules! request_code_write {
 ///
 /// You should only use this macro directly if the `ioctl` you're working
 /// with is "bad" and you cannot use `ioctl_readwrite!()` directly.
-#[macro_export]
+#[macro_export(local_inner_macros)]
 macro_rules! request_code_readwrite {
     ($ty:expr, $nr:expr, $sz:expr) => (ioc!($crate::sys::ioctl::READ | $crate::sys::ioctl::WRITE, $ty, $nr, $sz))
 }