Cross compiling Qt and dealing with teams
Let me share some notes on how Embedded Linux programming can be, if you decide the war/pain is over. We do this by looking at the desktop build and then look at the tons of stuff that you need for embedded programming.
Desktop
$ pkg-config –cflags libpng12
…
$ qmake && make
…
Embedded
$ . /usr/local/angstrom/arm/environment
$ pkg-config –cflags libpng12..
…
$ qmake-qt4 && make
Where is the difference?
There is little, you just use a cross compiler. The GNU/Linux Toolchain is prepared for cross compilation, pkg-config works with cross compilation.
What if I want different options
You can decide to use different -mtune and -march values, or you can easily regenerate the SDK targeting a different CPU architecture or just the instruction set level of it.
How is this possible
One creates a level of abstraction. The question is why do you want to suffer and don’t use the abstraction known from the desktop? The above is given to you by the Yocto/OpenEmbedded and details can be found in the OpenEmbedded Manual. Read here for more details on creating a Qt Toolchain/SDK and using it.
But I want to recompile Qt
Maybe you want to change the qconfig.h, or you have a bug in Qt where you want to test things more interactively. You could either do this in the build directory of Qt of Yocto/OpenEmbedded but then again the created SDK contains all the dependencies for building Qt. All that is missing is the generic qmake spec (that takes its values from the environment) that would need to be copied into mkspecs.
But my application needs libpainful-to-build
The SDK is deployed from header files of packages, you can install more -dev packages into your toolchain. If you use any of armv4t, armv5te, armv6, armv6-nofp, armv7, armv7a, … chances are high that there is already a build for your machine…
So why is it so painful?
I really don’t know, tell me.