[Crash-utility] 2.6.20 data structure changes

Just as a head's up, all of a sudden there are changes to some crucial data structures in 2.6.20 that break several commands, such as "vm", "files", "swap", "net -s", and probably more... I've fixed the "vm" and "swap" commands by recognizing that the file structure's former "f_dentry" and "f_vfsmnt" fields are now contained within the embedded "path" structure. That was simple enough... One of the other changes is the removal of the "max_fdset" field from the "fdtable" structure. I'm not entirely clear how best to handle it -- it almost seems that that if it doesn't exist, the "max_fds" value can be used alone in all cases where it used to be used in conjunction with "max_fdset"? Any filesystem-ophile out there that that can offer up a suggestion would be appreciated... I'll also fix the i386 "xgs" register addition to its pt_regs structure. Unfortunately the pt_regs register offsets have been hardwired in crash since the beginning of time (i.e., long before gdb was embedded in crash) and it's screwing up exception frame output... Dave