gRPC migration

Change-Id: I3129ae27d7ee12a23c7046f0d877e8064f2fd7f4
diff --git a/vendor/golang.org/x/sys/unix/asm_linux_amd64.s b/vendor/golang.org/x/sys/unix/asm_linux_amd64.s
index c6468a9..7ed38e4 100644
--- a/vendor/golang.org/x/sys/unix/asm_linux_amd64.s
+++ b/vendor/golang.org/x/sys/unix/asm_linux_amd64.s
@@ -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 !gccgo
+//go:build gc
+// +build gc
 
 #include "textflag.h"