Check if sort and tail are correctly built.

component/coreutils/buildout.cfg

@@ -19,7 +19,7 @@ environment =
 recipe = plone.recipe.command
 stop-on-error = true
 update-command = ${:command}
-command = ${:test} -x ${:test} -a -x ${:cat} -a -x ${:rm} -a -x ${:echo} -a -x ${:date} -a -x ${:md5sum} -a -x ${:basename}
+command = ${:test} -x ${:test} -a -x ${:cat} -a -x ${:rm} -a -x ${:echo} -a -x ${:date} -a -x ${:md5sum} -a -x ${:basename} -a -x ${:sort} -a -x ${:tail}
 test = ${coreutils:location}/bin/test
 cat = ${coreutils:location}/bin/cat
 rm = ${coreutils:location}/bin/rm
@@ -27,3 +27,5 @@ echo = ${coreutils:location}/bin/echo
 date = ${coreutils:location}/bin/date
 md5sum = ${coreutils:location}/bin/md5sum
 basename = ${coreutils:location}/bin/basename
+sort = ${coreutils:location}/bin/sort
+tail = ${coreutils:location}/bin/tail