${var:+"quo ted"} and similar, inside unquoted here-docs

[Ralf Wildenhues]

With Solaris 10 sh (and others):

cat <<EOF
${var-"quo  ted"}
EOF

"quo  ted"

Whereas with bash (and others):

quo  ted

This shows up in some of the log files in the "Configuring libtool" line:
http://autobuild.josefsson.org/libtool/log-201008291316239205000.txt

Eric, did you have this in your recent autoconf.texi additions already?
It can be a problem for all of the stuff that gets expanded into here
documents.

Thanks,
Ralf