Update to v4.17.3 kernel headers.

Test: Builds, boots on a walleye.
Change-Id: I389d8b61ec00ea309e38d1b1a2e0dace48c21edb
diff --git a/libc/kernel/uapi/asm-x86/asm/msgbuf.h b/libc/kernel/uapi/asm-x86/asm/msgbuf.h
index 7809e3c..92ab491 100644
--- a/libc/kernel/uapi/asm-x86/asm/msgbuf.h
+++ b/libc/kernel/uapi/asm-x86/asm/msgbuf.h
@@ -16,4 +16,23 @@
  ***
  ****************************************************************************
  ****************************************************************************/
+#ifndef __ASM_X64_MSGBUF_H
+#define __ASM_X64_MSGBUF_H
+#if !defined(__x86_64__) || !defined(__ILP32__)
 #include <asm-generic/msgbuf.h>
+#else
+struct msqid64_ds {
+  struct ipc64_perm msg_perm;
+  __kernel_time_t msg_stime;
+  __kernel_time_t msg_rtime;
+  __kernel_time_t msg_ctime;
+  __kernel_ulong_t msg_cbytes;
+  __kernel_ulong_t msg_qnum;
+  __kernel_ulong_t msg_qbytes;
+  __kernel_pid_t msg_lspid;
+  __kernel_pid_t msg_lrpid;
+  __kernel_ulong_t __unused4;
+  __kernel_ulong_t __unused5;
+};
+#endif
+#endif