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_ */