Fix conditional per-target flags for lexer
Fix conditional per-target flags for lexer

jianqiao/incubator-quickstep,hbdeshmukh/incubator-quickstep,tarunbansal/incubator-quickstep,cramja/incubator-quickstep,tarunbansal/incubator-quickstep,hbdeshmukh/incubator-quickstep,UWQuickstep/quickstep,hbdeshmukh/incubator-quickstep,jianqiao/incubator-quickstep,tarunbansal/incubator-quickstep,zuyu/incubator-quickstep,zuyu/incubator-quickstep,tarunbansal/incubator-quickstep,zuyu/incubator-quickstep,cramja/incubator-quickstep,UWQuickstep/quickstep,cramja/incubator-quickstep,cramja/incubator-quickstep,UWQuickstep/quickstep,UWQuickstep/quickstep,jianqiao/incubator-quickstep,zuyu/incubator-quickstep,UWQuickstep/quickstep,jianqiao/incubator-quickstep,hbdeshmukh/incubator-quickstep