I use Buildroot to make a Linux system for the Beaglebone Black. I configured Buildroot with the defalt configuration file. when I run "make", among other things Buildroot runs board/beagleboard/beaglebone/post-build.sh. I want to tweak this file for my needs, but I don't understand how it workes. Who calls it? What parameters it takes? Here is the script:

#!/bin/sh
BOARD_DIR="$(dirname $0)"
cp $BOARD_DIR/uEnv.txt $BINARIES_DIR/uEnv.txt
install -m 0644 -D $BOARD_DIR/extlinux.conf $BINARIES_DIR/extlinux/extlinux.conf

What are the values of BOARD_DIR and BINARIES_DIR?

I did an "echo TEST" to verfiy that script runs, and it does.