1 files changed, 3 insertions, 0 deletions
diff --git a/build.rs b/build.rs
index c83bff2..0604c19 100644
--- a/build.rs
+++ b/build.rs
@@ -16,4 +16,7 @@ fn main() {
     if ac.probe_rustc_version(1, 40) {
         println!("cargo:rustc-cfg=doctests");
     }
+    if ac.probe_rustc_version(1, 51) {
+        println!("cargo:rustc-cfg=raw_ref_macros");
+    }
 }