add test for issue #1466 that runs with CC ZEAL enabled.

Fixes #1466. (Unable to reproduce)

Author: nikomatsakis

src/test/run-pass/issue-1466.rs

@@ -1,3 +1,6 @@
+// exec-env:RUST_CC_ZEAL=1
+
 fn main() {
+    #error["%?", os::getenv("RUST_CC_ZEAL")];
     let _x = @{a: @10, b: ~true};
 }