Fixed detection of 'boolean' definition in GraphViz graph.h. Newer versions of GraphViz (2.16) include this definition, although it's not included in the older versions (2.12). Older versions still (2.8) are in use (Ubuntu 6.10 and Ubuntu 7.04).
trunk/SConstruct
trunk/base/generic/system/SConscript
trunk/base/generic/utilities/ascConfig.h