Property definitions

nitc $ SeparateCompilerVisitor :: can_be_primitive
	fun can_be_primitive(value: RuntimeVariable): Bool
	do
		var t = value.mcasttype.undecorate
		if not t isa MClassType then return false
		var k = t.mclass.kind
		return k == interface_kind or t.is_c_primitive
	end
src/compiler/separate_compiler.nit:2141,2--2147,4