diff --git a/AK/TestSuite.h b/AK/TestSuite.h
index f13b0a5fbf..623f666953 100644
--- a/AK/TestSuite.h
+++ b/AK/TestSuite.h
@@ -28,8 +28,6 @@
 
 #define AK_TEST_SUITE
 
-extern "C" __attribute__((noreturn)) void abort() noexcept;
-
 namespace AK {
 
 template<typename... Parameters>
@@ -63,6 +61,8 @@ using AK::warnln;
         ::abort();                                                                               \
     } while (false)
 
+#include <stdlib.h>
+
 #include <AK/Format.h>
 #include <AK/Function.h>
 #include <AK/NonnullRefPtrVector.h>