CRITICAL ISSUE: libc.so.6 lost in slackpkg upgrade-all

   Sony Vaio running stock 14.0/x86_64. After running 'slackpkg update' I ran
'slackpkg upgrade-all' and the screen went crazy with text scrolling by too
rapidly to read. This behavior is because libc.so.6 somehow was lost(!) and
everything depends on its presence ... including mount to try to restore
that package from the distribution DVD. Never in the 15 years I've run linux
has this happened to me. I'm well beyond my experience base and knowledge of
how to proceed.

   I've no idea what might have happened or why but do need to learn what I
need to do to restore the system to full working condition.

Advice and recommendations needed,

Rich