A little disclaimer: Many FOSS programs only offer Intel binaries because they happened to be built on an Intel machine. While there will be some which genuinely need the newer features from Snow Leopard etc., it is possible to build many on PPC.
Most Linux programs are available from Macports, but there are many which don't use Mac-native libraries (Cocoa in particular) and so pull in a ton of other Linux dependancies that you won't find many Mac-native applications using (GTK for example). The bottom line is that if you want to provide binaries of these projects for PowerPC Mac users then you need to strip out these dependancies and substitute them for something which doesn't require a ton of setup.
Anyway, LibreCAD looks to use Qt (instead of Cocoa or GTK), which provides a native UI for us Mac users. You will need to install the Qt devlopment kit. LibreCAD uses Qt 4, which is lucky because Qt 5 is not supported on PowerPC. Here is the download page:
http://qt-project.org/downloads. It's quite possible that they don't ship a PowerPC binary, in which case you will have to compile this from source (will take a while). You may want to install Macports to get this, otherwise you can find the source on the Qt downloads page. Also on the list of things to build is git (also in Macports), which you will need when working with just about any FOSS project.
So, on to the good stuff...
Get the dependancies:
Code:
sudo port install gitgcc46 qt4-creator-mac qt4-mac boost muparser
Change the gcc used to build ports:
Code:
sudo port select --set gcc mp-gcc46
Once you have these tools, it's simply a case of following the instructions they provide. Download the source, and compile:
Code:
git clone https://github.com/LibreCAD/LibreCAD.git
cd LibreCAD
qmake librecad.pro -r -spec mkspec/macports
make -j 2
You may change the number 2 to whatever your core count+1 is.
This should produce an executable .app.
Installing Macports:
http://trac.macports.org/wiki/InstallingMacPorts
Building ports from source:
http://trac.macports.org/wiki/UsingMacPortsQuickStart
You are going to need to install a bunch of stuff first - there are a few hoops to jump through.
First step is getting and installing the latest Xcode for PowerPC (I believe it's 3.x). This will provide you with the toolchain you'll be using to compile everything from now on.
