restructured build system support

cmake/scripts/RPi/rpi_path_helper.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+# This script can be used to set the path to the cross-compile toolchain
+# A default path is set if the path is not supplied via command line
+if [ $# -eq 1 ];then
+	export PATH=$PATH:"$1"
+else
+	# TODO: make version configurable via shell argument
+	export PATH=$PATH:"/opt/cross-pi-gcc/bin"
+	export CROSS_COMPILE="arm-linux-gnueabihf"
+	export RASPBERRY_VERSION="4"
+	export RASPBIAN_ROOTFS="${HOME}/raspberrypi/rootfs"
+fi
+
+# It is also recommended to set up a custom shell script to perform the
+# sysroot synchronization so that any software is built with the library and 
+# headers of the Raspberry Pi. This can for example be dome with the rsync
+# command. 
+# The following command can be used, <ip-address> and the local 
+# <rootfs-path> need to be set accordingly.
+
+# rsync -vR --progress -rl --delete-after --safe-links pi@<ip-address>:/{lib,usr,opt/vc/lib} <rootfs-path>
+
+# It is recommended to use $HOME/raspberrypi/rootfs as the rootfs path,
+# so the default RASPBIAN_ROOTFS variable set in the CMakeLists.txt is correct.