--- pngcheck-2.3.0/gpl/pngsplit.c.format	2007-02-11 22:46:23.000000000 +0100
+++ pngcheck-2.3.0/gpl/pngsplit.c	2017-09-18 01:59:24.622653474 +0200
@@ -141,8 +141,8 @@
                   0 == strncmp( argv[argn], "-quiet", 2 ) )
             verbose = 0;
         else {
-            fprintf(stderr, pngsplit_hdr);
-            fprintf(stderr, pngsplit_usage);
+            fprintf(stderr, "%s", pngsplit_hdr);
+            fprintf(stderr, "%s", pngsplit_usage);
             fflush(stderr);
             return 1;
         }
@@ -150,8 +150,8 @@
     }
 
     if ( argn == argc ) {
-        fprintf(stderr, pngsplit_hdr);
-        fprintf(stderr, pngsplit_usage);
+        fprintf(stderr, "%s", pngsplit_hdr);
+        fprintf(stderr, "%s", pngsplit_usage);
         fflush(stderr);
         return 5;
     } else {
@@ -162,7 +162,7 @@
 
     /*=============================  MAIN LOOP  =============================*/
 
-    fprintf(stdout, pngsplit_hdr);
+    fprintf(stdout, "%s", pngsplit_hdr);
     fflush(stdout);
 
     while (argn <= argc) {
--- pngcheck-2.3.0/gpl/png-fix-IDAT-windowsize.c.format	2006-06-17 23:42:13.000000000 +0200
+++ pngcheck-2.3.0/gpl/png-fix-IDAT-windowsize.c	2017-09-18 02:01:28.612729069 +0200
@@ -127,7 +127,7 @@
             fprintf(stderr, "  Compiled with zlib %s; using zlib %s.\n",
               ZLIB_VERSION, zlib_version);
             fprintf(stderr, "\n");
-            fprintf(stderr, png_fix_IDAT_windowsize_usage);
+            fprintf(stderr, "%s", png_fix_IDAT_windowsize_usage);
             fflush(stderr);
             return 1;
         }
@@ -143,7 +143,7 @@
     fflush(stdout);
 
     if ( argn == argc ) {
-        fprintf(stderr, png_fix_IDAT_windowsize_usage);
+        fprintf(stderr, "%s", png_fix_IDAT_windowsize_usage);
         fflush(stderr);
         return 5;
     } else {