Modified gdb for Lout

[Salman Khilji]

One of the things that is making it really hard for me to see the internals of 
lout OBJECTs in DDD is that these objects are too big to fit nicely in DDD 
windows.  Even if you want to look at succ and pred for PARENT and CHILD 
directions, you really have to expand all the unions really deep.  This 
situation arises simply because lout uses a "one size fits all" approach for 
the basic data type.

I modified gdb version 5.3 on Linux and taught it about Lout types.  I can now 
visually see the Lout types in DDD much more clearly.  Basically gdb shows 
only the variables in the structure that are of interest depending on the 
type of the variable.  So, for example, gdb fools the user into thinking that 
the actual OBJECT when its of type LINK is:

struct tGAP_OBJ_ {
  OBJECT _predPARENT_;
  OBJECT _succPARENT_;
  enum tLTYPE _type_;
  int _rec_size_;
  GAP _gap_;
  int _underline_;
  OBJECT _predCHILD_;
  OBJECT _succCHILD_;
};

Simarly when the actual object is EXT_GALL, then gdb shows only the following 
fields:

struct tEXT_GALL_ {
  OBJECT _predPARENT_;
  OBJECT _succPARENT_;
  enum tLTYPE _type_;
  int _rec_size_;
  int _eg_fnum_;
  int _eg_fpos_;
  int _eg_lnum_;
  int _eg_cont_;
  OBJECT _eg_symbol_;
  OBJECT _predCHILD_;
  OBJECT _succCHILD_;
};

And So forth.  I am aware of the built-in debug functionality and lout but if 
you are like me who gets spoiled by modern beasts known as debuggers, then 
simply "printf" style debugging is simply not enough.  One of the things that 
I tried to do was to call the function from gdb

call EchoObject <object of interest>

But gdb version 5.3 makes the target crash so often when you do this.

Will someone be interested in my patches for gdb?  The main purpose is for 
others to see it and probably modify my patches to make it useful to do 
normal modern type of debugging instead of printf style debugging.

Salman