Move LvalWantsBody into parser, from syntax
Move CheckSelection into parser, from syntax, replace ReportError -> yyerror
Move CheckConstraint into parser, from syntax, replace ReportError -> yyerror
Privatize ConstraintPostCheck in policy.c
Privatize ForceScalar from vars.h to matching.c, remove THIS_AGENT_TYPE escape
Privatize DefaultVarPromise from vars.h to cf-agent.c, constify
Remove IsCfList