diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index d4d567e63c017..6fc9423a4139a 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -10,6 +10,8 @@ filetime = "0.1"
 getopts = "0.2"
 log = "0.3"
 rustc-serialize = "0.3"
+
+[target.'cfg(unix)'.dependencies]
 libc = "0.2"
 
 [target.'cfg(windows)'.dependencies]