8.4.10's configure script suddenly started failing on platforms that use
older versions of ksh as /bin/sh.  It turns out to be a ksh bug that's
triggered by here-document delimiters falling across bufferload boundaries:
https://mailman.research.att.com/pipermail/ast-developers/2010q4/000797.html

Hopefully this will get fixed before we trip over it again, but to make
8.4.10 releasable, add a comment to move the boundaries to dodge the bug.
Per buildfarm members koi and warthog, plus a report from Bjorn Munch of
the identical failure on Solaris 10.