diff --git a/libc/include/android/legacy_sys_wait_inlines.h b/libc/include/android/legacy_sys_wait_inlines.h
new file mode 100644
index 0000000..63343eb
--- /dev/null
+++ b/libc/include/android/legacy_sys_wait_inlines.h
@@ -0,0 +1,49 @@
+/*
+ * 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.
+ */
+
+#ifndef _ANDROID_LEGACY_SYS_WAIT_INLINES_H_
+#define _ANDROID_LEGACY_SYS_WAIT_INLINES_H_
+
+#include <sys/cdefs.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#if __ANDROID_API__ < 18
+
+__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 /* __ANDROID_API__ < 18 */
+
+#endif /* _ANDROID_LEGACY_SYS_WAIT_INLINES_H_ */
diff --git a/libc/include/sys/wait.h b/libc/include/sys/wait.h
index 90eb35b..f3972fc 100644
--- a/libc/include/sys/wait.h
+++ b/libc/include/sys/wait.h
@@ -51,7 +51,11 @@
 
 pid_t wait(int*);
 pid_t waitpid(pid_t, int*, int);
+#if __ANDROID_API__ >= 18
 pid_t wait4(pid_t, int*, int, struct 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
@@ -63,4 +67,6 @@
 
 __END_DECLS
 
+#include <android/legacy_sys_wait_inlines.h>
+
 #endif /* _SYS_WAIT_H_ */