vdso handling

[Cary Coutant]

> I think a case can be made that gdb should be able to use the
> "execution view" of the program here.
> As for how to achieve that ... "Discuss." :-)

Add a PT_DEBUG program header entry? The PT_DEBUG segment would need
to have a small header that allows the debugger to find .debug_abbrev,
.debug_info, etc. (i.e., a mini section table). Or, just add
individual program header entries for each of the standard debug
sections: PT_DEBUG_ABBREV, PT_DEBUG_INFO, etc.

-cary