Yep, you may have an incorrect package path if you are using one of the popular architectures. The libc library was at 88.0 for 6.0-release, and in -current, as of several hours ago (and since 17 September) is at 89.2.
If you are using a $PKG_PATH environment variable, point it at snapshot packages, or if you are using pkg.conf(5), revise your
installpath string.
Note that -current is a constantly moving target, and you may still have to manually build the occasional port when using snapshot packages.
http://www.openbsd.org/faq/faq5.html#Flavors