Where a driver is built?

General
1

I tried to study how a driver is built . It is downloaded from github and built locally . Its build scrpt :

make_target() {
cd ${PKG_BUILD}/MT7668-Bluetooth
kernel_make EXTRA_CFLAGS=“-w”
KCFLAGS=“-Wno-int-conversion”
KERNEL_SRC=$(kernel_path)

}

I added an echo statement to it : echo ${PKG_BUILD} . But unfortunately , the print out is buried deeply at
one of a log files. Is there any way to know what the macro ${PKG_BUILD} means and where is the directory the deiver is built ?

By the way , the new version CoreELEC-Amlogic-no.aarch64-22.0-Piers_alpha1-Generic is built smoothly and quickly . Nice Job ~~~

2 
./scripts/build package_name

and you will see output on screen.

PKG_BUILD is package build folder like build.CoreELEC-Amlogic-no.aarch64-22/build/package_name-package_version/