Set GOPROXY to default if it is not configured

This is necessary since 'go env GOPROXY' will return an empty string if the
value is not set, thus setting GOPROXY to nothing.

Signed-off-by: Joonas Bergius <[email protected]>

Author: Joonas Bergius

Makefile

@@ -1,6 +1,8 @@
 # Use GOPROXY environment variable if set
 GOPROXY := $(shell go env GOPROXY)
-GOPROXY ?= https://proxy.golang.org
+ifeq ($(GOPROXY),)
+GOPROXY := https://proxy.golang.org
+endif
 export GOPROXY
 
 REGISTRY ?= gcr.io/$(shell gcloud config get-value project)