[VOL-4291] Rw-core updates for gRPC migration

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/golang.org/x/sys/unix/fdset.go b/vendor/golang.org/x/sys/unix/fdset.go
index b27be0a..a8068f9 100644
--- a/vendor/golang.org/x/sys/unix/fdset.go
+++ b/vendor/golang.org/x/sys/unix/fdset.go
@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos
 
 package unix