pathmatch no longer builds

[mqudsi]

With rust 1.18.0 (stable), the following error is produced when building pathmatch:

mqudsi@ZBook /m/c/U/M/g/static-compress> cargo build
    Updating registry `https://github.com/rust-lang/crates.io-index`
 Downloading pathmatch v0.1.2
   Compiling pathmatch v0.1.2
error: macros that expand to items must either be surrounded with braces or followed by a semicolon
  --> /home/mqudsi/.cargo/registry/src/github.com-1ecc6299db9ec823/pathmatch-0.1.2/src/pathmatch.rs:3:28
   |
3  |   macro_rules! return_if_some(
   |  ____________________________^ starting here...
4  | |     ($arg:expr) => (
5  | |         match $arg {
6  | |             Some(val) => return val,
7  | |             None => {},
8  | |         }
9  | |     );
10 | | )
   | |_^ ...ending here

error: aborting due to previous error

error: Could not compile `pathmatch`.

To learn more, run the command again with --verbose.