diff --git a/weaver/Makefile b/weaver/Makefile
index 38898deb..e5b53486 100644
--- a/weaver/Makefile
+++ b/weaver/Makefile
@@ -8,6 +8,13 @@ all: docker-image
 weaver: ../*.go main.go
 	go get -tags netgo
 	go build -ldflags '-extldflags "-static"' -tags netgo
+	@strings $@ | grep cgo_stub\\\.go >/dev/null || { \
+		rm $@; \
+		echo "\nYour go standard library was built without the 'netgo' build tag."; \
+		echo "To fix that, run"; \
+		echo "    sudo go install -a -tags netgo std"; \
+		false; \
+	}
 
 .PHONY: docker-image
 docker-image: /var/tmp/weave.tar