Test cowlib on all releases since R15B, plus maint and master

It passes on everything!

all.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+KERL_INSTALL_PATH=~/erlang
+KERL_RELEASES="r15b r15b01 r15b02 r15b03 r16b r16b01 r16b02 r16b03 r16b03-1 maint master"
+
+make build-tests
+
+for rel in $KERL_RELEASES
+do
+	echo
+	echo "    TESTING $rel"
+	echo
+	. $KERL_INSTALL_PATH/$rel/activate
+	cp ~/.kerl/builds/$rel/otp_src_*/lib/ssl/test/erl_make_certs.erl \
+		deps/ct_helper/src/
+	CT_OPTS="-label $rel" make tests
+done
+
+xdg-open logs/all_runs.html

erlang.mk

@@ -90,7 +90,13 @@ ALL_TEST_DEPS_DIRS = $(addprefix $(DEPS_DIR)/,$(TEST_DEPS))
 
 # Application.
 
-ERL_LIBS ?= $(DEPS_DIR)
+ifeq ($(filter $(DEPS_DIR),$(subst :, ,$(ERL_LIBS))),)
+ifeq ($(ERL_LIBS),)
+	ERL_LIBS = $(DEPS_DIR)
+else
+	ERL_LIBS := $(ERL_LIBS):$(DEPS_DIR)
+endif
+endif
 export ERL_LIBS
 
 ERLC_OPTS ?= -Werror +debug_info +warn_export_all +warn_export_vars \
@@ -210,13 +216,14 @@ build-tests: build-test-deps
 	$(gen_verbose) erlc -v $(ERLC_OPTS) -o test/ \
 		$(wildcard test/*.erl test/*/*.erl) -pa ebin/
 
+CT_OPTS ?=
 CT_RUN = ct_run \
 	-no_auto_compile \
 	-noshell \
 	-pa $(realpath ebin) $(DEPS_DIR)/*/ebin \
 	-dir test \
-	-logdir logs
-#	-cover test/cover.spec
+	-logdir logs \
+	$(CT_OPTS)
 
 CT_SUITES ?=