Update to kernel headers v4.12.3.

Test: Built angler.
Change-Id: Icbcf4fac2334de8409b049ed7a3b4c24b4e98ce9
diff --git a/libc/kernel/uapi/linux/snmp.h b/libc/kernel/uapi/linux/snmp.h
index 04a4603..91d693f 100644
--- a/libc/kernel/uapi/linux/snmp.h
+++ b/libc/kernel/uapi/linux/snmp.h
@@ -145,7 +145,6 @@
   LINUX_MIB_TIMEWAITED,
   LINUX_MIB_TIMEWAITRECYCLED,
   LINUX_MIB_TIMEWAITKILLED,
-  LINUX_MIB_PAWSPASSIVEREJECTED,
   LINUX_MIB_PAWSACTIVEREJECTED,
   LINUX_MIB_PAWSESTABREJECTED,
   LINUX_MIB_DELAYEDACKS,
@@ -208,6 +207,7 @@
   LINUX_MIB_SACKMERGED,
   LINUX_MIB_SACKSHIFTFALLBACK,
   LINUX_MIB_TCPBACKLOGDROP,
+  LINUX_MIB_PFMEMALLOCDROP,
   LINUX_MIB_TCPMINTTLDROP,
   LINUX_MIB_TCPDEFERACCEPTDROP,
   LINUX_MIB_IPRPFILTER,
@@ -227,6 +227,7 @@
   LINUX_MIB_TCPFASTOPENPASSIVEFAIL,
   LINUX_MIB_TCPFASTOPENLISTENOVERFLOW,
   LINUX_MIB_TCPFASTOPENCOOKIEREQD,
+  LINUX_MIB_TCPFASTOPENBLACKHOLE,
   LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES,
   LINUX_MIB_BUSYPOLLRXPACKETS,
   LINUX_MIB_TCPAUTOCORKING,