regent: minor fix in the undefined symbol detector
regent: minor fix in the undefined symbol detector

sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,sdalton1/legion,sdalton1/legion,StanfordLegion/legion,sdalton1/legion,chuckatkins/legion,sdalton1/legion,chuckatkins/legion,StanfordLegion/legion,chuckatkins/legion,sdalton1/legion,chuckatkins/legion,chuckatkins/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,chuckatkins/legion,StanfordLegion/legion