Merge rust-num#67

67: Compatible with cargo --remap-path-prefix r=cuviper a=dingelish

As discussed in [num-traits issue 139](rust-num/num-traits#139).

Co-authored-by: Yu Ding <dingelish@gmail.com>

Author: bors[bot]

build.rs

@@ -16,5 +16,5 @@ fn main() {
         autocfg::emit("has_const_fn");
     }
 
-    autocfg::rerun_path(file!());
+    autocfg::rerun_path("build.rs");
 }