# at-most-one-of ( gtk sdl )
app-emulation/vice -sdl

# at-most-one-of ( lcd_devices_hd44780 lcd_devices_hd44780-i2c )
app-misc/lcd4linux -lcd_devices_hd44780-i2c

# at-most-one-of ( cracklib pam )
sys-apps/shadow -cracklib

# at-most-one-of ( slz zlib )
net-proxy/haproxy -slz