build: Support IoT.js

Add make start helper

Relate-to: miroRucka#23
Origin: https://github.com/abandonware/bh1750
Change-Id: I38ac736a373702e87087d910ef30c91386d3a565
Relate-to: miroRucka#25
Forwarded: https://github.com/miroRucka/bh1750/pulls
Signed-off-by: Philippe Coval <rzr@users.sf.net>

Makefile

@@ -0,0 +1,40 @@
+#!/bin/make -f
+# -*- makefile -*-
+# SPDX-License-Identifier: MIT
+
+default: help all
+	@echo "log: $@: $^"
+
+tmp_dir ?= tmp
+runtime ?= iotjs
+export runtime
+srcs_dir ?= lib example
+srcs ?= $(wildcard *.js | sort | uniq)
+
+main_src ?= example/index.js
+
+
+help:
+	@echo "## Usage: "
+	@echo "# make start"
+
+setup: setup/${runtime}
+
+start/%: ${main_src}
+	${@F} $< ${run_args}
+
+start: start/${runtime}
+
+clean:
+	rm -rf ${tmp_dir}
+
+cleanall: clean
+	rm -f *~
+
+distclean: cleanall
+	rm -rf node_modules
+
+setup/iotjs: ${iotjs_modules_dir}
+	@echo "Expected to see IoT.js' help"
+	${@F} --help ||:
+	ls $<