diff --git a/libc/include/android/legacy_sys_wait_inlines.h b/libc/include/android/legacy_sys_wait_inlines.h
deleted file mode 100644
index eadc752..0000000
--- a/libc/include/android/legacy_sys_wait_inlines.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (C) 2016 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <sys/cdefs.h>
-
-#if __ANDROID_API__ < 18
-
-#include <sys/syscall.h>
-#include <sys/wait.h>
-#include <unistd.h>
-
-__BEGIN_DECLS
-
-static __inline pid_t wait4(pid_t pid, int* status, int options, struct rusage* rusage) {
-  return __BIONIC_CAST(static_cast, pid_t, syscall(__NR_wait4, pid, status, options, rusage));
-}
-
-__END_DECLS
-
-#endif
diff --git a/libc/include/sys/wait.h b/libc/include/sys/wait.h
index 8c0655f..96974a2 100644
--- a/libc/include/sys/wait.h
+++ b/libc/include/sys/wait.h
@@ -26,8 +26,7 @@
  * SUCH DAMAGE.
  */
 
-#ifndef _SYS_WAIT_H_
-#define _SYS_WAIT_H_
+#pragma once
 
 #include <bits/wait.h>
 #include <sys/cdefs.h>
@@ -40,11 +39,7 @@
 
 pid_t wait(int* __status);
 pid_t waitpid(pid_t __pid, int* __status, int __options);
-#if __ANDROID_API__ >= 18
 pid_t wait4(pid_t __pid, int* __status, int __options, struct rusage* __rusage) __INTRODUCED_IN(18);
-#else
-// Implemented as a static inline before 18.
-#endif
 
 /* Posix states that idtype_t should be an enumeration type, but
  * the kernel headers define P_ALL, P_PID and P_PGID as constant macros
@@ -55,7 +50,3 @@
 int waitid(idtype_t __type, id_t __id, siginfo_t* __info, int __options);
 
 __END_DECLS
-
-#include <android/legacy_sys_wait_inlines.h>
-
-#endif