Proposed fix is in rt46276.  It avoids wreaking havoc in generated
documentation by enabling expansion only for explicitly specified
macros.  A cursory search through the source tree did not uncover any
further candidates for special-casing like this, but if it turns out to
be necessary, more macros may easily be added by following the examples
from Doxygen documentation [1].

Please review.

[1] http://www.doxygen.nl/config.html