Ported the latest Voodoo patches from PCem.

src/include/86box/vid_ddc.h

@@ -0,0 +1,4 @@
+void ddc_init(void);
+void ddc_i2c_change(int new_clock, int new_data);
+int ddc_read_clock(void);
+int ddc_read_data(void);