diff --git a/Package.swift b/Package.swift
index 39c6fb4b2f..02c08b898d 100644
--- a/Package.swift
+++ b/Package.swift
@@ -26,7 +26,7 @@
     .target(name: "NIOFoundationCompat", dependencies: ["NIO"]),
     .target(name: "CNIOAtomics", dependencies: []),
     .target(name: "CNIOSHA1", dependencies: []),
-    .target(name: "CNIOLinux", dependencies: []),
+    .target(name: "CNIOLinux", dependencies: [], cSettings: [.define("_GNU_SOURCE")]),
     .target(name: "CNIODarwin", dependencies: [], cSettings: [.define("__APPLE_USE_RFC_3542")]),
     .target(name: "CNIOWindows", dependencies: []),
     .target(name: "NIOConcurrencyHelpers",