Hi,
You need to set the BSEC_DIR environment variable to the file system path where the Bosch Bsec library can be found. If you run make yellow_wp77xx, it should give you some more helpful error messages. But, basically, you download the zip file from the link below and unzip it in your components/boschBsec directory.
Alternatively, if you don’t care about using the environmental sensor, you can comment-out the environment app and the related bindings in yellow.sdef.
–Jen