patch to use target specific .gdbinit file

[Andrew Cagney]

>> > Here's a question: does a multi-targetted gdb know what it's targetting
> 
> at
> 
>> > the point of reading the .gdbinit or is this determined later?  Is it
>> > switchable per session?  I'm thinking that another possibility is to
> 
> have it
> 
>> > check for .gdbinit-$TARGET at the time that the target is determined.
> 
>>
>> To clarify something here, target and architecture are separate but very
>> related.  GDB configured for a certain TARGET, will support one or more
>> architectures.  The x86-64, for instance, also supports i386.
>>
>> For a normal GDB session, an architecture will be selected twice.  Once
>> for the default, and once based on the file that is loaded.  The second
>> selection may occure before, during or after, .gdbinit parsing.  The
>> `target' however, won't change.
> 
> 
> So, to clarify further, a single gdb binary can only support a single target
> but multiple architectures?

A single gdb executable can support multiple `target architectures'. 
Those architectures, as with i386 / x86-64 are not necessarily of the 
same family.

A single gdb executable can support multiple `target interfaces'.  For 
instance, remote, pmon, and ptrace.

A single gdb executable's configuration options (target interfaces, 
target architectures, initial architecture, ....) are selected by the 
--target=TARGET option (and in the future --enable-targets=...).

>  If this is the case then your method of
> enabling this at config time would be just fine.  I was thinking of a (for
> instance) ppc/x86 gdb but I didn't think that was possible which was what I
> wanted to ask.

Er, that is a single gdb executable supporting ``multiple architectures''.

Andrew