diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index 170300a..af96eff 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -50,26 +50,26 @@
 #define POSIX_MADV_DONTNEED   MADV_DONTNEED
 
 #if defined(__USE_FILE_OFFSET64)
-extern void* mmap(void*, size_t, int, int, int, off_t) __RENAME(mmap64);
+extern void* mmap(void*, size_t, int, int, int, off_t) __RENAME(mmap64) __INTRODUCED_IN(21);
 #else
 extern void* mmap(void*, size_t, int, int, int, off_t);
 #endif
-extern void* mmap64(void*, size_t, int, int, int, off64_t);
+extern void* mmap64(void*, size_t, int, int, int, off64_t) __INTRODUCED_IN(21);
 
 extern int munmap(void*, size_t);
 extern int msync(const void*, size_t, int);
 extern int mprotect(const void*, size_t, int);
 extern void* mremap(void*, size_t, size_t, int, ...);
 
-extern int mlockall(int);
-extern int munlockall(void);
+extern int mlockall(int) __INTRODUCED_IN(21);
+extern int munlockall(void) __INTRODUCED_IN(21);
 extern int mlock(const void*, size_t);
 extern int munlock(const void*, size_t);
 
 extern int mincore(void*, size_t, unsigned char*);
 
 extern int madvise(void*, size_t, int);
-extern int posix_madvise(void*, size_t, int);
+extern int posix_madvise(void*, size_t, int) __INTRODUCED_IN(23);
 
 __END_DECLS