Bug 157827: declare the exported PBE_ functions.  Fixed the include-once ifdef.
Bug 157827: declare the exported PBE_ functions.  Fixed the include-once
ifdef.

nmav/nss,ekr/nss-old,ekr/nss-old,ekr/nss-old,ekr/nss-old,ekr/nss-old,nmav/nss,nmav/nss,nmav/nss,nmav/nss,nmav/nss,nmav/nss,ekr/nss-old,ekr/nss-old