I'd wager a guess it's more a case of lacking functionality on behalf of bcc, than bmk.
Exactly. While mark has said that the source to BMK will be released, I doubt the source to BCC will be released any time soon, if ever.
(For those confused as to the difference, in as simple a form as I can manage: BCC does the actual grunt work of compiling the source code to the required platform, BMK just pulls the files together and links them together with any static libraries).