+void SourcePackage::Loader::if_feature(const string &cond)
+{
+ bool match = false;
+ string::size_type equals = cond.find('=');
+ if(equals!=string::npos)
+ {
+ if(equals==0)
+ throw invalid_argument("SourcePackage::Loader::if_feature");
+ bool negate = cond[equals-1]=='!';
+ string name = cond.substr(0, equals-negate);
+ string value = obj.config.get_option("with_"+name).value;
+ match = (value==cond.substr(equals+1))!=negate;
+ value = cond.substr(equals+1);
+ }
+ else
+ {
+ bool negate = (cond[0]=='!');
+ string name = cond.substr(negate);
+ string value = obj.config.get_option("with_"+name).value;
+ match = lexical_cast<bool>(value)!=negate;
+ }
+ obj.builder.get_logger().log("configure", format("%s: feature %s %smatched", obj.name, cond, (match ? "" : "not ")));
+ if(match)
+ load_sub_with(*this);
+}
+
+void SourcePackage::Loader::source_tarball()