Method AddMacro

libs/wgtcc/cpp.h:112–119

            std::string* text, bool preDef = false);

        void AddMacro(const std::string& name, const Macro& macro) {
            auto res = macroMap_.find(name);
            if (res != macroMap_.end()) {
                // TODO(wgtdkp): give warning
                macroMap_.erase(res);
            }
            macroMap_.insert(std::make_pair(name, macro));
        }

        void RemoveMacro(const std::string& name) {
            auto res = macroMap_.find(name);