Remove useless #ifdef.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@7625 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/png.c

@@ -25,7 +25,6 @@
  * - use filters when generating a png (better compression)
  */
 
-#ifdef CONFIG_ZLIB
 #include <zlib.h>
 
 //#define DEBUG
@@ -886,4 +885,3 @@ AVImageFormat png_image_format = {
     png_write,
     AVIMAGE_INTERLEAVED,
 };
-#endif