Added preliminary emulation of the 'Xebec' XT Fixed Disk Adapter.

src/Makefile.linux64

@@ -9,7 +9,7 @@ codegen.o codegen_ops.o codegen_timing_486.o codegen_timing_686.o codegen_timing
 dac.o device.o disc.o disc_fdi.o disc_img.o disc_sector.o dma.o fdc.o fdc37c665.o fdd.o fdi2raw.o gameport.o \
 hdd.o headland.o i430lx.o i430fx.o i430vx.o ide.o intel.o intel_flash.o io.o jim.o joystick_ch_flightstick_pro.o joystick_standard.o joystick_sw_pad.o \
 joystick_tm_fcs.o keyboard.o keyboard_amstrad.o keyboard_at.o keyboard_olim24.o keyboard_pcjr.o keyboard_xt.o \
-lpt.o mcr.o mem.o mfm_at.o model.o mouse.o mouse_ps2.o mouse_serial.o neat.o nmi.o nvr.o olivetti_m24.o \
+lpt.o mcr.o mem.o mfm_at.o mfm_xebec.o model.o mouse.o mouse_ps2.o mouse_serial.o neat.o nmi.o nvr.o olivetti_m24.o \
 opti495.o pc.o pci.o pic.o piix.o pit.o ppi.o ps1.o ps2.o rom.o rtc.o scat.o serial.o sis496.o sound.o \
 sound_ad1848.o sound_adlib.o sound_adlibgold.o sound_cms.o sound_emu8k.o sound_gus.o \
 sound_mpu401_uart.o sound_opl.o sound_pas16.o sound_ps1.o sound_pssj.o sound_sb.o sound_sb_dsp.o sound_sn76489.o \