Disable CGO for improved compatibility across distros (#420)

* Disable CGO for improved compatibility across distros

* Enabled CGO in tests for the race detector

Makefile

@@ -4,6 +4,9 @@ export PATH := $(shell pwd)/.tmp/protoc/bin:$(PATH)
 
 export PROTOC_VERSION := 22.0
 
+# Disable CGO for improved compatibility across distros
+export CGO_ENABLED=0
+
 # TODO: run golint and errcheck, but only to catch *new* violations and
 # decide whether to change code or not (e.g. we need to be able to whitelist
 # violations already in the code). They can be useful to catch errors, but
@@ -89,7 +92,8 @@ errcheck:
 
 .PHONY: test
 test:
-	go test -race ./...
+	# The race detector requires CGO: https://github.com/golang/go/issues/6508
+	CGO_ENABLED=1 go test -race ./...
 
 .tmp/protoc/bin/protoc: ./Makefile ./download_protoc.sh
 	./download_protoc.sh