I'm trying to compile boost (1.57 on linux RHEL6) which doesn't have bzip2 installed. (See https://github.com/Homebrew/linuxbrew/pull/322) Therefore to get it to work I can set BZIP2_INCLUDE and BZIP2_LIBPATH to my custom bzip2 install. Is there any way to add a directory to the search path of all header files/libraries for B2? I was assuming not otherwise there would be no need for the BZIP2_* and ZLIB_* environment variables.