and undef if a rebuild could be needed in some circumstances, but is not
strictly required.
-### targetpage
-
- hook(type => "targetpage", id => "foo", call => \&targetpage);
-
-This hook can be used to override the name of the file a page should
-be compiled into.
-
-It should return the target filename.
-
## Plugin interface
To import the ikiwiki plugin interface: