diff --git a/Makefile b/Makefile
index 92da377f8ea..3b953942f6d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,8 @@
+# This is a Makefile which maintains files automatically generated but to be
+# shipped together with other files.
+# You don't have to rebuild these targets by yourself unless you develop
+# grpc-gateway itself.
+
 PKG=github.com/gengo/grpc-gateway
 GO_PLUGIN=bin/protoc-gen-go
 GO_PLUGIN_PKG=github.com/golang/protobuf/protoc-gen-go
@@ -55,9 +60,11 @@ test: examples
 	go test $(PKG)/...
 
 clean distclean:
-realclean:
+	rm -f $(GATEWAY_PLUGIN)
+realclean: distclean
 	rm -f $(OPTIONS_GO)
 	rm -f $(EXAMPLE_SVCSRCS) $(EXAMPLE_DEPSRCS)
 	rm -f $(EXAMPLE_GWSRCS)
+	rm -f $(GO_PLUGIN)
 
 .PHONY: generate examples test clean distclean realclean
diff --git a/examples/examplepb/a_bit_of_everything.pb.go b/examples/examplepb/a_bit_of_everything.pb.go
index 5c9f422c36e..582ed7eff82 100644
--- a/examples/examplepb/a_bit_of_everything.pb.go
+++ b/examples/examplepb/a_bit_of_everything.pb.go
@@ -14,10 +14,6 @@ import (
 	grpc "google.golang.org/grpc"
 )
 
-// Reference imports to suppress errors if they are not otherwise used.
-var _ context.Context
-var _ grpc.ClientConn
-
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
 
@@ -77,6 +73,10 @@ func (m *IdMessage) Reset()         { *m = IdMessage{} }
 func (m *IdMessage) String() string { return proto.CompactTextString(m) }
 func (*IdMessage) ProtoMessage()    {}
 
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
 // Client API for ABitOfEverythingService service
 
 type ABitOfEverythingServiceClient interface {
diff --git a/examples/examplepb/echo_service.pb.go b/examples/examplepb/echo_service.pb.go
index daf0fac99d9..80a74f5fadd 100644
--- a/examples/examplepb/echo_service.pb.go
+++ b/examples/examplepb/echo_service.pb.go
@@ -23,10 +23,6 @@ import (
 	grpc "google.golang.org/grpc"
 )
 
-// Reference imports to suppress errors if they are not otherwise used.
-var _ context.Context
-var _ grpc.ClientConn
-
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
 
@@ -38,6 +34,10 @@ func (m *SimpleMessage) Reset()         { *m = SimpleMessage{} }
 func (m *SimpleMessage) String() string { return proto.CompactTextString(m) }
 func (*SimpleMessage) ProtoMessage()    {}
 
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
 // Client API for EchoService service
 
 type EchoServiceClient interface {
diff --git a/runtime/context_test.go b/runtime/context_test.go
index 4e1bec641f6..d004a0f3dfc 100644
--- a/runtime/context_test.go
+++ b/runtime/context_test.go
@@ -2,6 +2,7 @@ package runtime_test
 
 import (
 	"net/http"
+	"reflect"
 	"testing"
 
 	"github.com/gengo/grpc-gateway/runtime"
@@ -25,10 +26,10 @@ func TestAnnotateContext(t *testing.T) {
 	if !ok || len(md) != 2 {
 		t.Errorf("Expected 2 metadata items in context; got %v", md)
 	}
-	if md["Foobar"] != "Value1" {
-		t.Errorf("md[\"Foobar\"] = %v; want %v", md["Foobar"], "Value1")
+	if got, want := md["Foobar"], []string{"Value1"}; !reflect.DeepEqual(got, want) {
+		t.Errorf("md[\"Foobar\"] = %v; want %v", got, want)
 	}
-	if md["Foo-Baz"] != "Value2" {
-		t.Errorf("md[\"Foo-Baz\"] = %v want %v", md["Foo-Baz"], "Value2")
+	if got, want := md["Foo-Baz"], []string{"Value2"}; !reflect.DeepEqual(got, want) {
+		t.Errorf("md[\"Foo-Baz\"] = %v want %v", got, want)
 	}
 }