diff --git a/Userland/Libraries/LibCore/AnonymousBuffer.cpp b/Userland/Libraries/LibCore/AnonymousBuffer.cpp
index 6caeb22e5d..d3087363b2 100644
--- a/Userland/Libraries/LibCore/AnonymousBuffer.cpp
+++ b/Userland/Libraries/LibCore/AnonymousBuffer.cpp
@@ -24,10 +24,6 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#if defined(__linux__) && !defined(_GNU_SOURCE)
-#    define _GNU_SOURCE // For memfd_create, MFD_CLOEXEC
-#endif
-
 #include <LibCore/AnonymousBuffer.h>
 #include <LibIPC/Decoder.h>
 #include <LibIPC/Encoder.h>