Change calls to error_msg.* and strerror to use perror_msg.*.
diff --git a/grep.c b/grep.c
index 9014443..8333661 100644
--- a/grep.c
+++ b/grep.c
@@ -169,7 +169,7 @@
 			file = fopen(cur_file, "r");
 			if (file == NULL) {
 				if (!suppress_err_msgs)
-					error_msg("%s: %s\n", cur_file, strerror(errno));
+					perror_msg("%s", cur_file);
 			}
 			else {
 				grep_file(file);