Add posix_fadvise(3).

(cherry-pick of 00008263782e484020420c606f7d145fe7d0a4d8.)

Bug: 12449798
Change-Id: I07cbf3f670a0d1304b68148325a774f266b5c433
diff --git a/libc/arch-x86_64/syscalls/__fadvise64.S b/libc/arch-x86_64/syscalls/__fadvise64.S
new file mode 100644
index 0000000..8810d88
--- /dev/null
+++ b/libc/arch-x86_64/syscalls/__fadvise64.S
@@ -0,0 +1,17 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(__fadvise64)
+    movq    %rcx, %r10
+    movl    $__NR_fadvise64, %eax
+    syscall
+    cmpq    $-MAX_ERRNO, %rax
+    jb      1f
+    negl    %eax
+    movl    %eax, %edi
+    call    __set_errno_internal
+1:
+    ret
+END(__fadvise64)
+.hidden __fadvise64