Build system changes for 4.2.0

This page describes changes to the 4.2.0 build system.

Environment variables are no longer required or honoured.
The image, prefix and SDK location are now explicitly specified. See Image, prefix and SDK location for details.
The default image is now located in <build>/image instead of <build>/image/opt/Qtopia.
The RPATH is implcitly set to <prefix>/lib unless you pass -no-rpath.
Host libs go in <build>/lib/host to avoid clashes with target libs.
Big syntax changes in qmake (whitespace and quoting are very different).
Classic includes are not located at <build>include/classic and Qt-style includes are located at <build>/include.
New hint=themecfg for translatable strings in themes.
New library qtopiabase that sits between Qtopia and Qtopia Core, resolving some dependency issues.
Only 1 icon size is used.
New hint=non_qt_headers which is required due to the switch to using Qt-style headers by default.
.desktop files are no longer installed. Instead, their contents are put into the PREFIX database.
New hint=script for scripts that need to know where the PREFIX is.
link_test can operate on both Qtopia and Qtopia Core plugins (including quicklaunched apps). It's currently opt-in.
qtopiacore projects (libraries and plugins) are installed from their directories instead of src/qt.