9c: another gcc, another useless warning

bin/9c

diff --git a/bin/9c b/bin/9c
index fe6776c..327f167 100755
--- a/bin/9c
+++ b/bin/9c
@@ -73,7 +73,7 @@
 $cc -DPLAN9PORT -I$PLAN9/include $cflags "$@" 2>$xtmp
 status=$?
 grep -v '__p9l_autolib_' $xtmp |
-egrep -v ': error: .Each undeclared identifier|: error: for each function it appears|is dangerous, better use|is almost always misused|: In function |: At top level:|support .long long.|In file included from|        from|use of C99 long long|ISO C forbids conversion|Cursor. is deprecated' |
+egrep -v ': error: .Each undeclared identifier|: error: for each function it appears|is dangerous, better use|is almost always misused|: In function |: At top level:|support .long long.|In file included from|        from|use of C99 long long|ISO C forbids conversion|Cursor. is deprecated|warn_unused_result' |
 sed 's/ .first use in this function.$//; s/\"\([^\"][^\"]*\)\", line \([0-9][0-9]*\)/\1:\2/g' |
 uniq 1>&2
 rm -f $xtmp $xtmp.status