Merge pull request #929 from dpacbach/warnings-fix

Fix some minor warnings found with a recent clang version

include/spdlog/common.h

@@ -193,7 +193,7 @@ struct source_loc
     }
     SPDLOG_CONSTEXPR source_loc(const char *filename, int line)
         : filename(filename)
-        , line(line)
+        , line(static_cast<uint32_t>(line))
     {
     }
 

include/spdlog/details/log_msg.h

@@ -37,7 +37,6 @@ struct log_msg
     }
 
     log_msg(const log_msg &other) = default;
-    log_msg &operator=(const log_msg &other) = default;
 
     const std::string *logger_name{nullptr};
     level::level_enum level{level::off};