diff --git a/Userland/Libraries/LibC/serenity.h b/Userland/Libraries/LibC/serenity.h
index 7771026a11c900..c60625494b19d9 100644
--- a/Userland/Libraries/LibC/serenity.h
+++ b/Userland/Libraries/LibC/serenity.h
@@ -22,6 +22,11 @@ int profiling_free_buffer(pid_t);
 
 int futex(uint32_t* userspace_address, int futex_op, uint32_t value, const struct timespec* timeout, uint32_t* userspace_address2, uint32_t value3);
 
+#ifndef ALWAYS_INLINE
+#    define ALWAYS_INLINE inline __attribute__((always_inline))
+#    define ALWAYS_INLINE_SERENITY_H
+#endif
+
 static ALWAYS_INLINE int futex_wait(uint32_t* userspace_address, uint32_t value, const struct timespec* abstime, int clockid)
 {
     int op;
@@ -42,6 +47,10 @@ static ALWAYS_INLINE int futex_wake(uint32_t* userspace_address, uint32_t count)
     return futex(userspace_address, FUTEX_WAKE, count, NULL, NULL, 0);
 }
 
+#ifdef ALWAYS_INLINE_SERENITY_H
+#    undef ALWAYS_INLINE
+#endif
+
 int purge(int mode);
 
 int perf_event(int type, uintptr_t arg1, uintptr_t arg2);
diff --git a/Userland/Libraries/LibC/sys/cdefs.h b/Userland/Libraries/LibC/sys/cdefs.h
index 15ee0b0a8d6106..00d6444102737c 100644
--- a/Userland/Libraries/LibC/sys/cdefs.h
+++ b/Userland/Libraries/LibC/sys/cdefs.h
@@ -8,10 +8,6 @@
 
 #define _POSIX_VERSION 200809L
 
-#ifndef ALWAYS_INLINE
-#    define ALWAYS_INLINE inline __attribute__((always_inline))
-#endif
-
 #ifdef __cplusplus
 #    ifndef __BEGIN_DECLS
 #        define __BEGIN_DECLS extern "C" {