I am seeing a strange discrepancy between building the headers target from the command line vs including it as a dependency in another target. In our own projects we 'use-project /boost : $(PATH_TO_BOOST) ;' and use the headers target. But as a reproducible example, if I add /boost//headers to tools/quickbook/src/Jamfile.v2 I get: http://pastebin.com/KMcMSLZW I tried to debug it, but alas my skills at boost-build seem to be insufficient. It is interesting to note however that when looking at 'b2 -d5' output 'sequence.join library-name-headers .' seems to be invoked when it fails, yet that does not occur when it succeeds. If anyone has any ideas on how to get this working again, I would be happy to look into this more. -- Thomas I for one welcome our new git overlords.