Rebar downloading via inets & bumbped otp vsn requirements

Makefile

@@ -1,12 +1,20 @@
 PROJECT = esqlite
-REBAR = ./rebar
 DIALYZER = dialyzer
 
+REBAR := $(shell which rebar 2>/dev/null || echo ./rebar)
+REBAR_URL := https://github.com/downloads/basho/rebar/rebar
+
 all: compile
 
-rebar:
-	wget https://github.com/downloads/basho/rebar/rebar -O $(REBAR)
-	chmod u+x $(REBAR)
+#rebar:
+#	wget https://github.com/downloads/basho/rebar/rebar -O $(REBAR)
+#	chmod u+x $(REBAR)
+
+./rebar:
+	erl -noshell -s inets start -s ssl start \
+        -eval '{ok, saved_to_file} = httpc:request(get, {"$(REBAR_URL)", []}, [], [{stream, "./rebar"}])' \
+        -s inets stop -s init stop
+	chmod +x ./rebar
 
 compile: rebar
 	$(REBAR) compile

rebar.config

@@ -1,3 +1,3 @@
-{require_otp_vsn, "R14"}.
+{require_otp_vsn, "R14|R15|R16"}.
 {port_env, [{"CFLAGS", "$CFLAGS -DSQLITE_THREADSAFE=1 -DSQLITE_USE_URI -DSQLITE_ENABLE_FTS3 -DSQLITE_ENABLE_FTS3_PARENTHESIS"}]}.
 {port_specs, [{"priv/esqlite3_nif.so", ["c_src/*.c"]}]}.