Replace fDATIME with ANSI/POSIX clock_gettime(). Rip out DOS/AMIGA shims.

The thinking here is that we simplify life by going pure ANSI/POSIX.
This is a text game.  If it ever runs on anything but Unix again it's
almost certain to be on something like WSL that supplies a
POSIX-conformant text console.

misc.c

@@ -898,10 +898,6 @@ long I, VAL; static FILE *OPENED = NULL;
 	 goto L20;
 
 L15:	if(!OPENED){
-#ifdef AMIGA
-		OPENED=fopen("ram:adventure.text","r" /* NOT binary */);
-		if(!OPENED)
-#endif
 		OPENED=fopen("adventure.text","r" /* NOT binary */);
 		if(!OPENED){printf("Can't read adventure.text!\n"); exit(FALSE);}
 		}