Making CFLAGS=-g1 bigger but more useful

[Paolo Bonzini]

> The basic question though is whether there is interest here for this
> sort of -g1.5 mode.  We could ...

Yes, definitely.  I thought about it in two contexts -- regular
debugging, and the fact that the OpenCL GSOC project might require
looking at debug info for memory spaces and types of arguments.

> - ignore the value of this enlarged -g1 and forget the idea
> 
> - adopt the enlarged definition for -g1 and live with the size penalty
> 
> - introduce a new -g1.5 (between DINFO_LEVEL_TERSE and DINFO_LEVEL_NORMAL)
>   to select the enlarged definition (syntax suggestions wanted)

Another possibility, though a much bigger amount of work, would be to
introduce -g options like -f.  The presence of such an option would
imply -g1 or higher, and then you could add -gparameters,
-gline-numbers, -gvar-tracking, -gmacros, etc.

Paolo