[libng16] Conditionally compile png_inflate(). It's not needed for iCCP

chunk reading.

ANNOUNCE

-Libpng 1.6.25beta01 - August 11, 2016
+Libpng 1.6.25beta01 - August 12, 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.
@@ -25,9 +25,10 @@ Other information:
 
 Changes since the last public release (1.6.24):
 
-Version 1.6.25beta01 [August 11, 2016]
+Version 1.6.25beta01 [August 12, 2016]
   Reject oversized iCCP profile immediately.
   Cleaned up PNG_DEBUG compile of pngtest.c.
+  Conditionally compile png_inflate().
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -5675,9 +5675,10 @@ Version 1.6.24rc03 [August 2, 2016]
 Version 1.6.24[August 4, 2016]
   No changes.
 
-Version 1.6.25beta01 [August 11, 2016]
+Version 1.6.25beta01 [August 12, 2016]
   Reject oversized iCCP profile immediately.
   Cleaned up PNG_DEBUG compile of pngtest.c.
+  Conditionally compile png_inflate().
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

pngrutil.c

@@ -461,6 +461,7 @@ png_zlib_inflate(png_structrp png_ptr, int flush)
 #endif /* Zlib >= 1.2.4 */
 
 #ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
 /* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
  * allow the caller to do multiple calls if required.  If the 'finish' flag is
  * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
@@ -590,7 +591,6 @@ png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
    }
 }
 
-#if defined(PNG_READ_zTXt_SUPPORTED) || defined (PNG_READ_iTXt_SUPPORTED)
 /*
  * Decompress trailing data in a chunk.  The assumption is that read_buffer
  * points at an allocated area holding the contents of a chunk with a