treewide: more log_*_errno() conversions

src/core/load-dropin.c

@@ -71,7 +71,7 @@ static int iterate_dir(
                 de = readdir(d);
                 if (!de && errno != 0) {
                         k = errno;
-                        log_error("Failed to read directory %s: %s", path, strerror(k));
+                        log_error_errno(k, "Failed to read directory %s: %m", path);
                         return -k;
                 }
 

src/core/main.c

@@ -354,7 +354,7 @@ static int parse_proc_cmdline_item(const char *key, const char *value) {
                         if (env)
                                 arg_default_environment = env;
                         else
-                                log_warning("Setting environment variable '%s' failed, ignoring: %s", value, strerror(ENOMEM));
+                                log_warning_errno(ENOMEM, "Setting environment variable '%s' failed, ignoring: %m", value);
                 } else
                         log_warning("Environment variable name '%s' is not valid. Ignoring.", value);