diff --git a/build.rs b/build.rs
index 6137608..ca991a5 100644
--- a/build.rs
+++ b/build.rs
@@ -71,6 +71,11 @@
         println!("cargo:rustc-cfg=num_nonzero");
     }
 
+    // Current minimum supported version of serde_derive crate is Rust 1.31.
+    if minor >= 31 {
+        println!("cargo:rustc-cfg=serde_derive");
+    }
+
     // TryFrom, Atomic types, and non-zero signed integers stabilized in Rust 1.34:
     // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto
     // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#library-stabilizations