Switch to thread_local crate in lieu of thread_local!.

This is to work around a bug where using a thread_local! was causing
a segfault on macos.

Fixes #164.

1 files changed, 1 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 7c4937ce..1b702790 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,6 +38,7 @@ num_cpus = "1"
 regex = "0.1.77"
 rustc-serialize = "0.3"
 term = "0.4"
+thread_local = "0.2.7"
 walkdir = "0.1"
 
 [target.'cfg(windows)'.dependencies]