One of the most useful ways of compiling software for the powerpc is to make use of the ppa repositories. You'll find many of these mentioned in the forums where developers can upload newer versions of packaged programs or programs that are not officially available in Ubuntu, or where there is some issue that prevents automatic builds, for example a dependency is missing.
Since Ubuntu is only officially supported for x86 architectures, if a developer submits code to a ppa it is only automatically built for x86 (and x64) and so no packages appear in Synaptic for users of other architectures.
However, the source code is available and it includes all the necessary 'extras' to make deb installer packages so that once installed you can use Synaptic to view, uninstall whatever and all the program files go into the right places.
To compile a package is easy, let's say you want to compile the program 'foo'. Firstly you need to install the necessary build packages:
Then make a new directory to work in and cd into it
sudo apt-get install build-essential fakeroot dpkg-dev
Add the required ppa repository to your repository list and update
then download the source
sudo add-apt-repository ppa:foo
sudo apt-get update
This will download and extract the source code tree. Once complete there will be a new subdirectory in your build directory, cd into it:
You need to make sure you have all the dependencies installed:
Then the clever bit:
sudo apt-get build-dep foo
(If you have a multi-core machine you can speed up the build by adding a 'jobs' flag:
dpkg-buildpackage -rfakeroot -b
Have a cup of tea. When the compilation is finished cd back up to the build directory:
dpkg-buildpackage -rfakeroot -b -j4
There you will (if all went well) find one or more 'deb' files, which you install with:
I only learned this a few months ago and now it's second nature. I found it on this site:
sudo dpkg -i ./*.deb
I found some of the steps used on that site were unneccesary and some of the 'sudo' use was unneccessary too so my method is a little neater.
For some packages I have found that sometimes you have to build some of the dependencies too. You just have to run through this same process for the dependency first.
I regularly use this process for the unity-2d ppa and for vlc on powerpc.