Update to v4.17.3 kernel headers.

Test: Builds, boots on a walleye.
Change-Id: I389d8b61ec00ea309e38d1b1a2e0dace48c21edb
diff --git a/libc/kernel/uapi/linux/shm.h b/libc/kernel/uapi/linux/shm.h
index a3071e7..a30a089 100644
--- a/libc/kernel/uapi/linux/shm.h
+++ b/libc/kernel/uapi/linux/shm.h
@@ -65,6 +65,7 @@
 #define SHM_UNLOCK 12
 #define SHM_STAT 13
 #define SHM_INFO 14
+#define SHM_STAT_ANY 15
 struct shminfo {
   int shmmax;
   int shmmin;