[Bug debug/46749] gcc.dg/debug/pr41893-1.c -gdwarf-2 testsuite failures on darwin

[mikestump at comcast dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46749

--- Comment #35 from Mike Stump <mikestump at comcast dot net> 2010-12-05 21:13:30 UTC ---
Surely this design isn't complete as it doesn't cover the changes or the
requirements for lto.  Without those, I can't review the design to see if it is
sufficient to actually fix the problem at hand.  The problem is there are
temporary files removed by subpasses during the subpass.  The above doesn't
lengthen the lifetime of those temporary files, so can't fix the problem.

Compare and contrast another potential design:

Add an environment variable that identifies a file in which additions can be
made of temporary object files to remove once the link is done.  If any subpart
of the compilation process wants to create to create intermediate .o files,
they can instead write into that named file, the names of the temporary files
to delete, then the top level driver (one with no environment variable set, can
delete them, at the very end.  This even works for linker plugin files and
cover just about every type of tech or architecture for the compilation process
save distribution, caching and compilation server.  I'd propose we handle those
later, as necessary.

The advantages of this over the last one is, it is complete, it would always
work, regardless of nesting complexities, doesn't require any changes to `ld',
and works, even when collect2 isn't used.