How to recompile Qt with Digi Embedded Linux 5.8

On a Linux PC where you have installed your Digi Embedded Linux ESP and toolchain, typically under /usr/local/DigiEL-*/ create a local working directory and change into it. E:g.

# mkdir ~/DEL58toolchain
# cd ~/DEL58toolchain

Mount the Digi Embedded Linux DVD and copy toolchain files to your working directory:
# cp -a /media/DigiEL_LiveDVD/toolchain/del_toolchain/* `pwd`

Change permissions as DVD was maybe mounted read only:
# chmod -R +rwX .

Change to the directory of the package you want to recompile, e.g. for Qt:
# cd packages/qt-embedded

Copy the original package sources:
# cp /media/DigiEL_LiveDVD/toolchain/packages/qt-everywhere-opensource-src-4.7.2.tar.gz `pwd`

Point to the Digi cross compiling toolchain, e.g.:
# export TOOLCHAIN_DIR=/usr/local/DigiEL-5.8/x-tools/arm-cortex_a8-liunx-gnueabi/

Optionally modify the arguments you want to pass to ./configure in Makefile.in
# vi/edit/emacs Makefile.in

Deflate sources, apply Digi patches and do complete compilation:
# make

Depending on the package you will need to install the build results (e.g. binaries, config- and data files) to your rootfs. Check the makefile for INSTALL_DIR and "make install" or copy the files manually. E.g.:
# make install

will install to a local _install folder, while:
# make install-del

will install into your toolchain directory, overwriting /usr/local/DigiEL-*/
So the latter will change those files for all your projects. Sometimes you only want to change them for one project, so you should use the add_files.sh method in your local project.