diff -urN cvs-1.12.13/diff/diff3.c cvs-1.12.13.new/diff/diff3.c
--- cvs-1.12.13/diff/diff3.c	2004-10-09 17:51:52.000000000 +0200
+++ cvs-1.12.13.new/diff/diff3.c	2013-02-05 21:38:47.024405045 +0100
@@ -1503,7 +1503,7 @@
 	      line = 0;
 	      do
 		{
-		  printf_output (line_prefix);
+		  printf_output ("%s", line_prefix);
 		  cp = D_RELNUM (ptr, realfile, line);
 		  length = D_RELLEN (ptr, realfile, line);
 		  write_output (cp, length);
diff -urN cvs-1.12.13/src/main.c cvs-1.12.13.new/src/main.c
--- cvs-1.12.13/src/main.c	2013-02-05 21:33:06.000000000 +0100
+++ cvs-1.12.13.new/src/main.c	2013-02-05 21:43:02.996351658 +0100
@@ -1475,7 +1475,7 @@
 {
     (void) fprintf (stderr, *cpp++, program_name, cvs_cmd_name);
     for (; *cpp; cpp++)
-	(void) fprintf (stderr, *cpp);
+	(void) fputs (*cpp, stderr);
     exit (EXIT_FAILURE);
 }