Minor change in ifdef for clarity

include/spdlog/logger-inl.h

@@ -247,10 +247,10 @@ SPDLOG_INLINE void logger::err_handler_(const std::string &msg)
         auto tm_time = details::os::localtime(system_clock::to_time_t(now));
         char date_buf[64];
         std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
-#if !defined(R_R_H) || !defined(USING_R)
-        std::fprintf(stderr, "[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
-#else // compiled in R environment
+#if defined(USING_R) && defined(R_R_H) // if in R environment
         REprintf("[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
+#else
+        std::fprintf(stderr, "[*** LOG ERROR #%04zu ***] [%s] [%s] {%s}\n", err_counter, date_buf, name().c_str(), msg.c_str());
 #endif
     }
 }