**Note**: Sometimes basic pkgsrc tools; *bmake*, *pkg_install* and *bootstrap-mk-files* need to be upgraded. However, they can't be deleted and replaced since you need that tool to accomplish replacement. The solution is to build a separate package before deletion, and install that package.
# cd /usr/pkgsrc/devel/bmake
+ # cd /usr/pkgsrc/pkgtools/pkg_install
+ # cd /usr/pkgsrc/pkgtools/bootstrap-mk-files
# env USE_DESTDIR=yes bmake package
# bmake clean-depends clean