Technical criteria for retaining symbol readers

[Michael Elizabeth Chastain]

jimb> I'd also like to have some kind of requirement for testability.

I would, too.  My preference would be that we look at gdb-testers@
and if there are no test results for feature X for the past N years,
that counts against keeping feature X.  gcc uses that as one factor
in deciding whether to obsolete stuff.

As far as Andrew's original proposal goes, it's okay with me to
set up some criteria for dropping formats.

Michael C