only use -it on ttys

Author: rv32ima

Makefile

@@ -187,9 +187,17 @@ define user_confirm
 	fi
 endef
 
+# https://stackoverflow.com/questions/4251559/how-can-i-tell-if-a-makefile-is-being-run-from-an-interactive-shell
+INTERACTIVE:=$(shell [ -t 0 ] && echo 1)
+ifdef INTERACTIVE
+	DOCKER_OPTIONS="-it"
+else
+	DOCKER_OPTIONS=""
+endif
+
 # $(call DOCKER, image, command)
 define DOCKER
-	docker run -it --rm -e GOCACHE=/app/.cache -e IN_DOCKER=1 -w /app -v $(PWD):/app -v $(GOPATH):/go --init $(1) /bin/bash -c '$(2)'
+	docker run "$(DOCKER_OPTIONS)" --rm -e GOCACHE=/app/.cache -e IN_DOCKER=1 -w /app -v $(PWD):/app -v $(GOPATH):/go --init $(1) /bin/bash -c '$(2)'
 endef
 
 ifeq ($(BUILD_IN_DOCKER),y)
@@ -213,6 +221,7 @@ else
 	PATHSEP = :
 endif
 
+
 v_at_0 = yes
 v_at_ = $(v_at_1)
 quiet := $(v_at_$(V))