It doesn't matter if you recompile it from source. Wine isn't an emulator. The way it works is by translating Windows function calls from Windows applications to the equivalent Unix ones. This fools the Windows application into thinking that it's running on Windows, and as there isn't any emulation involved, the applications usually run really fast.
Recompiling it from source will not help at all since the PowerPC processor architecture is vastly different from x86, hence the need for emulators. That's why there's a project like Darwine, dedicated to porting WINE over to the PowerPC machines.