[Bug lto/49992] lto-bootstrap reveals duplicate symbols on x86_64-apple-darwin11

["iains at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49992

--- Comment #26 from Iain Sandoe <iains at gcc dot gnu.org> 2011-08-09 15:40:38 UTC ---
(In reply to comment #25)
> (In reply to comment #23)
> 
> > and ...  watch out for the first case matching all darwin ;-) and the second
> > never firing.
> 
> Why would you say that? I believe we have many instances of
> *-apple-darwin[[3-9]]* in the configure.ac's of FSF gcc.

misread the patch .. 

===

but - I'm not sure what you mean by  "ranlib before Darwin10 requires the -c
flag to look at common symbols. "

Where is it documented that there is some different behavior of Darwin 9 (or 8,
for that matter)?

what  "ranlib -c" does is to put common symbols into the archive symbol table.

the common symbols are still present in each archive object with (or without)
"-c" (so they can be 'seen' if a module is loaded that uses them)..

So, the case that would require '-c' is if a common symbol must be found in the
archive table of contents ... this (as the man page says) seems like an
unlikely scenario.

Mike: can you recall why this was done and what problem it solved?