diff --git a/Cargo.toml b/Cargo.toml
index 74737a4..58572c7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,6 +8,7 @@
 repository = "https://github.com/alexcrichton/proc-macro2"
 homepage = "https://github.com/alexcrichton/proc-macro2"
 documentation = "https://docs.rs/proc-macro2"
+build = "build.rs"
 description = """
 A stable implementation of the upcoming new `proc_macro` API. Comes with an
 option, off by default, to also reimplement itself in terms of the upstream