[patch/rfc] Build inf-ptrace.o when ptrace available

[Andrew Cagney]

> We can't "get GNU/Linux [...] using procfs".

Is there a technical problem blocking this?

>>> Why is it orthogonal?  If we assume that configure determines when /proc 
>>> and ptrace() and provides both to the user it certainly isn't.  Idea's 
>>> such as Mark's and mine would make it easier.
> 
> 
> Why is it related?  How would this make it easier?  It's not hard to
> add a new backend file to all the Linux targets; it's really not much
> different in a lot of little files than in one big one.  I've done this
> plenty of times.

If we used configure.tgt and:
	switch "$target"
	 *-*-linux* ) "objs=objs symfile-mem.c"
	esac
then all GNU/Linux systems will always and consistently include 
symtab-mem.c.  We don't, they don't ...

We've already got configure.tgt checking OSABI and configure.host 
checking FLOATFORMAT so there's plenty of prior art.  Further, 
modifying/merging just that file is going to be a lot easier than 
modifying/merging all the individual *.mh files.

Andrew