"struct target_ops" -> "struct gdbtarg" || "struct target"

[Andrew Cagney <ac131313 at redhat dot com>]

Hello,

The current "target_ops" structure appeared with GDB 4.  The original 
implementation containing only methods.  Since then the target_ops have 
evolved to include data vis:

    struct section_table
     *to_sections;
    struct section_table
     *to_sections_end;

I think, the vector should be re-named to "struct target" or "struct 
gdbtarg" (consistent with gdbarch, and more name space proof) so that it 
correctly reflects its current implementation.

I'd like to do this now, before the target methods start being 
explicitly parameterized with their target vector.

thoughts?
Andrew