[boost] can emacs cc-mode be made to do boost-style preprocessor indents?

The Boost style of nested indenting for preprocessor directives is nice. I'm using cc-mode for emacs (the sourceforge version), and it doesn't seem to directly support this: #if 1 # if 2 # define A 1 # else # endif #endif I found this cc-mode mailing list discussion that confirmed the lack of support: http://sourceforge.net/mailarchive/forum.php?thread_id=5382045&forum_id=6827 Anyone already got some working elisp for preprocessor autoindent?