source type(c)
    "driver-select.c",
    "drv-ascii.c",
    "drv-mps803.c",
    "drv-nl10.c",
    "drv-raw.c",
    "interface-serial.c",
    "interface-userport.c",
    "output-graphics.c",
    "output-text.c",
    "output-select.c",
    "printer.c",
    "printer-serial.c",
    "printer-userport.c"
