LocaleRules: define includesSeparator
libbe.so catalog: fixed headers search.

* use SEARCH_SOURCE instead of SEARCH, it's also used for headers search
* add print to UsePrivateHeaders, needed for pr_server.h
<build>linkcatkeys was failing to run on Haiku r1a4 correctly.

* linking against the host libbe.so which could also contain classes
like DefaultCatalog seems to let the runtime_loader in trouble.
* as a workaround we rename the class.