[libpng16] Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate

"tmpfile()" implementation in contrib/libtests/pngstest.c

ANNOUNCE

-Libpng 1.6.22beta01 - January 16, 2016
+Libpng 1.6.22beta01 - January 17, 2016
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -25,7 +25,9 @@ Other information:
 
 Changes since the last public release (1.6.21):
 
-Version 1.6.22beta01 [January 16, 2016]
+Version 1.6.22beta01 [January 17, 2016]
+  Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate
+    "tmpfile()" implementation in contrib/libtests/pngstest.c
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -5484,7 +5484,9 @@ Version 1.6.21rc02 [January 7, 2016]
 Version 1.6.21 [January 15, 2016]
   Worked around a false-positive Coverity issue in pngvalid.c.
 
-Version 1.6.22beta01 [January 16, 2016]
+Version 1.6.22beta01 [January 17, 2016]
+  Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate
+    "tmpfile()" implementation in contrib/libtests/pngstest.c
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

contrib/libtests/pngstest.c

 /*-
  * pngstest.c
  *
- * Copyright (c) 2013-2015 John Cunningham Bowler
+ * Copyright (c) 2013-2016 John Cunningham Bowler
  *
- * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Last changed in libpng 1.6.22 [(PENDING RELEASE)]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -3096,7 +3096,7 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
 
    if (image->opts & USE_STDIO)
    {
-#ifndef PNG_USE_MKSTEMP
+#ifndef __COVERITY__
       FILE *f = tmpfile();
 #else
       /* Experimental. Coverity says tmpfile() is insecure because it