rpmbuild --rebuild qpid-proton-0.27.0-3.el6.src.rpm

CMake Warning:
  Manually-specified variables were not used by the project:

    BUILD_PERL
    CMAKE_INSTALL_LIBDIR
    SHARE_INSTALL_PREFIX
    SYSCONF_INSTALL_DIR

I did not investigate where the unused variables are coming from. I guess the BUILD_PERL must be our custom, the other may be injected from some generic RPM template for CMake...