diff -ur watchdog-5.15.old/src/test_binary.c watchdog-5.15/src/test_binary.c
--- watchdog-5.15.old/src/test_binary.c	2016-02-26 12:05:00.000000000 +0000
+++ watchdog-5.15/src/test_binary.c	2018-02-13 08:51:27.292750445 +0000
@@ -263,11 +263,11 @@
 		 * to cause trouble, so make them go to their respective files */
 		strcpy(filename_buf, logdir);
 		strcat(filename_buf, "/test-bin.stdout");
-		if (!freopen(filename_buf, "a+", stdout))
+		if (!freopen(filename_buf, "a", stdout))
 			exit(errno);
 		strcpy(filename_buf, logdir);
 		strcat(filename_buf, "/test-bin.stderr");
-		if (!freopen(filename_buf, "a+", stderr))
+		if (!freopen(filename_buf, "a", stderr))
 			exit(errno);
 
 		/* now start binary */
diff -ur watchdog-5.15.old/src/watchdog.c watchdog-5.15/src/watchdog.c
--- watchdog-5.15.old/src/watchdog.c	2016-02-26 12:05:00.000000000 +0000
+++ watchdog-5.15/src/watchdog.c	2018-02-13 08:51:43.747738628 +0000
@@ -86,11 +86,11 @@
 		 * So make stdout and stderr go to their respective files */
 		strcpy(filename_buf, logdir);
 		strcat(filename_buf, "/repair-bin.stdout");
-		if (!freopen(filename_buf, "a+", stdout))
+		if (!freopen(filename_buf, "a", stdout))
 			exit(errno);
 		strcpy(filename_buf, logdir);
 		strcat(filename_buf, "/repair-bin.stderr");
-		if (!freopen(filename_buf, "a+", stderr))
+		if (!freopen(filename_buf, "a", stderr))
 			exit(errno);
 
 		/* now start binary */