gdb/633: fully qualified pathnames in solib_map_sections() and remote debugging

[Andrew Cagney]

>> > I think the search order needs some revision though:
>> >  - A cross debugger should not search $PATH or $LD_LIBRARY_PATH
> 
>> 
>> I agree with this.
>> 
> 
>> >  - A cross debugger may, or may not, want to look for the unmodified
>> > path; I suspect that we only want to look for unmodified relative
>> > paths, not unmodified absolute ones.
> 
>> 
>> I agree regarding absolute paths.
>> 
>> For relative paths, I'm not convinced that it's all that useful to
>> look at the unmodified path.  (Doing so requires that you have your
>> cwd set correctly, right?)
> 
> 
> Yes; I think that's not too unreasonable, though.  I can go either way
> on this one; I believe it never comes up in GNU/Linux since the linker
> fills in the full path in the link map.  Not 100% sure of that,
> however.
> 
> 
>> > With those changes you would have to explicitly specify the path to
>> > DSOs in a cross debugger via solib-absolute-prefix and
>> > solib-search-path,
> 
>> 
>> I think this would be good...
>> 
> 
>> > and GDB would stop picking up the host libpthread.so
>> > and making gdbserver segfault...
> 
>> 
>> ...and this too!
> 
> 
> This leaves only the question of "how".  I don't want to change the
> behavior for a native debugger using the remote protocol; just for
> non-native debuggers.  How should I check for this?  Using configury to
> do it seems contrary to the direction gdbarch is going (i.e. a both
> native and cross debugger in one binary).

This is a target environment thing?  So why not ask the target:

target_getenv()
	-> qGetenv:<STRING>
	<- value

Andrew