Update to v4.19 kernel headers.

Test: Builds and boots.
Change-Id: I99a9ed79666e143b47f02ca4e59eed94f69b7e4a
diff --git a/libc/kernel/uapi/asm-x86/asm/sembuf.h b/libc/kernel/uapi/asm-x86/asm/sembuf.h
index 9b7e109..9b96722 100644
--- a/libc/kernel/uapi/asm-x86/asm/sembuf.h
+++ b/libc/kernel/uapi/asm-x86/asm/sembuf.h
@@ -20,10 +20,17 @@
 #define _ASM_X86_SEMBUF_H
 struct semid64_ds {
   struct ipc64_perm sem_perm;
+#ifdef __i386__
+  unsigned long sem_otime;
+  unsigned long sem_otime_high;
+  unsigned long sem_ctime;
+  unsigned long sem_ctime_high;
+#else
   __kernel_time_t sem_otime;
   __kernel_ulong_t __unused1;
   __kernel_time_t sem_ctime;
   __kernel_ulong_t __unused2;
+#endif
   __kernel_ulong_t sem_nsems;
   __kernel_ulong_t __unused3;
   __kernel_ulong_t __unused4;