Since it might need several attempts to get the kernels compiled at first start of a new version to enable OpenCL following little script can do the annoying stuff:
#!/bin/bash
while true; do
str=`/Applications/darktable.app/Contents/MacOS/darktable-cltest | grep "OpenCL successfully initialized."`
if [[ $str =~ "OpenCL" ]]; then
echo "openCL enabled"
break
fi
done