Update to kernel headers v4.12.3.

Test: Built angler.
Change-Id: Icbcf4fac2334de8409b049ed7a3b4c24b4e98ce9
diff --git a/libc/include/bits/glibc-syscalls.h b/libc/include/bits/glibc-syscalls.h
index 3191a23..3f99dcb 100644
--- a/libc/include/bits/glibc-syscalls.h
+++ b/libc/include/bits/glibc-syscalls.h
@@ -1063,6 +1063,9 @@
 #if defined(__NR_statfs64)
   #define SYS_statfs64 __NR_statfs64
 #endif
+#if defined(__NR_statx)
+  #define SYS_statx __NR_statx
+#endif
 #if defined(__NR_stime)
   #define SYS_stime __NR_stime
 #endif