[gprof] disjoint histograms

[Vladimir Prus]

Hi Nick, Hi Ben,

> >> My one suggested addition would be that you could add an entry in the 
> >> binutils/NEWS file mentioning this new feature of gprof.
> > 
> > Perhaps even gprof.texi, if applicable?
> 
> I think both.  The NEWS files are used to make release notes for each 
> new version of the binutils and I think that it would be nice to include 
> a mention of Vladimir's new feature.

I certainly can update both NEWS and gprof.texi and post a new patch.
I'll do that in a couple of days provided no objections to the
code patch itself will show up.

- Volodya