There are two unrelated sed issues with pkgsrc/print/pdflib:
pkgsrc's Makefile.common has:

SUBST_CLASSES+=                sed
SUBST_STAGE.sed=       pre-configure
SUBST_FILES.sed=       configure pdflib-config.in
SUBST_SED.sed=         -e "s| sed | ${SED} |g"
SUBST_SED.sed=         -e "s|^sed |${SED} |g"

this however does not replace all occurrences of sed (occurrences like
|sed is missed) in the two files.
It would probaly be better to have ${SED} linked to .tools/bin/sed,
similarly as 
USE_GNU_TOOLS+=                sed
does it for GNU sed. Does buildlink provide a mechanism for it, or does
it have to be done explicitly, as post-tools for example?

A second, unrelated, issue is the following:

when configuring pdflib-4.0.3 (regardless whether as part of pkgsrc or
standalone) I get:

creating tiff/Makefile
sed: command garbled: s%@DEFS@%
creating flate/Makefile
sed: command garbled: s%@DEFS@%
creating png/Makefile
sed: command garbled: s%@DEFS@%
creating Makefile
sed: command garbled: s%@DEFS@%
creating pdflib-config
sed: command garbled: s%@DEFS@%
creating pdflib/Makefile
sed: command garbled: s%@DEFS@%
creating test/Makefile
sed: command garbled: s%@DEFS@%
creating clients/Makefile
sed: command garbled: s%@DEFS@%
creating util/Makefile
sed: command garbled: s%@DEFS@%
creating bind/c/Makefile
sed: command garbled: s%@DEFS@%

and the Makefiles are not created. This happens with both by platform's
(IRIX 5.3) native sed as well as with gnu sed (4.0.9).
When I change the line
s%@DEFS@%$DEFS%g
in configure into
s%@DEFS@%\$DEFS%g
it seems to work. I don't know why this occurs or whether my solution
has any negative side effects.
Strangely, the problem does not occur on a Slackware Linux system, for
example.


-- 
Georg Schwarz    http://home.pages.de/~schwarz/
 geos@epost.de     +49 177 8811442