Rewrote the disc sector poller again for simplified code and more accuracy;

Floppy formats are now accurately timed and also more accurately implemented;
Applied all mainline PCem commits.

src/x86_ops_int.h

@@ -1,6 +1,3 @@
-/* Copyright holders: Sarah Walker
-   see COPYING for more details
-*/
 static int opINT3(uint32_t fetchdat)
 {
         if ((cr0 & 1) && (eflags & VM_FLAG) && (IOPL != 3))
@@ -70,7 +67,7 @@ static int opINTO(uint32_t fetchdat)
         }
         if (VF_SET())
         {
-                oldpc = cpu_state.pc;
+                cpu_state.oldpc = cpu_state.pc;
                 x86_int_sw(4);
                 return 1;
         }