Comment # 4 on bug 1223783 from Richard Biener

Note one important step will be to make sure (at least for the shared
libraries) that no symbols are removed.  Ideally that should be the case for
the static libraries as well - we've had multiple issues here in the past with
lapack
deprecating APIs and not building them by default when not specially asked.

That might be OK for openSUSE but for old SLES codestreams we have to be
careful.  I'm not sure for SLE15 -> SLE16 compatibility but breaking the
shared library ABI would be bad.