diff --git a/Cargo.lock b/Cargo.lock
index c9d6a8eb7a2..4fe24f06886 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3392,6 +3392,7 @@ version = "1.0.0"
 dependencies = [
  "byteorder",
  "crossbeam-utils 0.7.2",
+ "libc",
  "proc-macro2",
  "quote",
  "serde",
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index 337d65e4da4..11b175f9e80 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/src/tools/rustc-workspace-hack/Cargo.toml
@@ -64,6 +64,7 @@ features = [
 byteorder = { version = "1", features = ['default', 'std'] }
 curl-sys = { version = "0.4.13", features = ["http2", "libnghttp2-sys"], optional = true }
 crossbeam-utils = { version = "0.7.2", features = ["nightly"] }
+libc = { version = "0.2.79", features = ["align"] }
 proc-macro2 = { version = "1", features = ["default"] }
 quote = { version = "1", features = ["default"] }
 serde = { version = "1.0.82", features = ['derive'] }