Add check_rebar target to the Makefile to fetch rebar3 if it doesn't exist.

Author: cabol

Makefile

@@ -1,4 +1,4 @@
-REBAR = $(shell which rebar3 || echo ./rebar3)
+REBAR = $(shell which rebar3)
 
 ## Common variables
 CONFIG ?= test/test.config
@@ -11,25 +11,36 @@ CT_BUILD_PATH = $(CT_PATH)/lib/*/ebin
 CT_SUITES = task_SUITE local_SUITE dist_SUITE
 CT_OPTS = -cover test/cover.spec -erl_args -config ${CONFIG}
 
-.PHONY: all compile clean distclean dialyze tests shell doc
+.PHONY: all check_rebar compile clean distclean dialyze tests shell doc
 
-all: compile
+all: check_rebar compile
 
-compile:
+check_rebar:
+ifeq ($(REBAR),)
+ifeq ($(wildcard rebar3),)
+	curl -O https://s3.amazonaws.com/rebar3/rebar3
+	chmod a+x rebar3
+	$(eval REBAR=./rebar3)
+else
+	$(eval REBAR=./rebar3)
+endif
+endif
+
+compile: check_rebar
 	$(REBAR) compile
 
-clean:
+clean: check_rebar
 	rm -rf ebin/* test/*.beam logs log
 	$(REBAR) clean
 
 distclean: clean
 	$(REBAR) clean --all
 	rm -rf _build logs log edoc *.dump c_src/*.o priv/*.so
 
-dialyze:
+dialyze: check_rebar
 	$(REBAR) dialyzer
 
-tests:
+tests: check_rebar
 	$(REBAR) as test compile
 	mkdir -p $(CT_PATH)/logs
 	ct_run -dir test -suite $(CT_SUITES) -pa $(CT_BUILD_PATH) -logdir $(CT_PATH)/logs $(CT_OPTS)