#TODO: help_string & usage_string:

gui/about.cpp
gui/browser.cpp
gui/chooser.cpp
gui/error.cpp
gui/gui-manager.cpp
gui/KeysDialog.h
gui/KeysDialog.cpp
gui/launcher.cpp
gui/massadd.cpp
gui/options.cpp
gui/saveload-dialog.cpp
gui/themebrowser.cpp
gui/ThemeEngine.cpp
gui/widget.cpp
gui/fluidsynth-dialog.cpp

base/main.cpp

common/error.cpp
common/util.cpp

engines/advancedDetector.cpp
engines/dialogs.cpp
engines/engine.cpp

audio/fmopl.cpp
audio/mididrv.cpp
audio/musicplugin.cpp
audio/null.h
audio/null.cpp
audio/softsynth/adlib.cpp
audio/softsynth/appleiigs.cpp
audio/softsynth/sid.cpp
audio/softsynth/mt32.cpp
audio/softsynth/pcspk.cpp

backends/keymapper/remap-dialog.cpp
backends/midi/windows.cpp
backends/platform/sdl/macosx/appMenu_osx.mm
backends/graphics/surfacesdl/surfacesdl-graphics.cpp
backends/events/default/default-events.cpp
backends/updates/macosx/macosx-updates.mm