Rename _Exit in a way that works with libandroid_support.

Bug: N/A
Test: builds
Change-Id: I2aeaf9bafe7d51e91b67f22d68f4e52191df062b
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 86336a0..cf0dea8 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -43,7 +43,12 @@
 
 __noreturn void abort(void);
 __noreturn void exit(int __status);
+#if __ANDROID_API__ >= __ANDROID_API_L__
 __noreturn void _Exit(int __status) __INTRODUCED_IN(21);
+#else
+__noreturn void _Exit(int) __RENAME(_exit);
+#endif
+
 int atexit(void (*__fn)(void));
 
 int at_quick_exit(void (*__fn)(void)) __INTRODUCED_IN(21);