Fixed treatment of debug/tracing preprocessor flags in expression.c
Fixed treatment of debug/tracing preprocessor flags in expression.c

johnty/libmapper,radarsat1/libmapper,radarsat1/libmapper,libmapper/libmapper,johnty/libmapper,libmapper/libmapper,radarsat1/libmapper,malloch/libmapper,johnty/libmapper,malloch/libmapper,libmapper/libmapper,malloch/libmapper,malloch/libmapper,libmapper/libmapper,malloch/libmapper,libmapper/libmapper,radarsat1/libmapper,johnty/libmapper,radarsat1/libmapper,libmapper/libmapper,johnty/libmapper,malloch/libmapper