Make ff_png_pass_xmin and ff_png_pass_xshift static to png.c.

Signed-off-by: Janne Grunau <janne-ffmpeg@jannau.net>
(cherry picked from commit f2e246f576)

libavcodec/png.c

@@ -31,12 +31,12 @@ const uint8_t ff_png_pass_ymask[NB_PASSES] = {
 };
 
 /* minimum x value */
-const uint8_t ff_png_pass_xmin[NB_PASSES] = {
+static const uint8_t ff_png_pass_xmin[NB_PASSES] = {
     0, 4, 0, 2, 0, 1, 0
 };
 
 /* x shift to get row width */
-const uint8_t ff_png_pass_xshift[NB_PASSES] = {
+static const uint8_t ff_png_pass_xshift[NB_PASSES] = {
     3, 3, 2, 2, 1, 1, 0
 };
 

libavcodec/png.h

@@ -55,12 +55,6 @@ extern const uint8_t ff_mngsig[8];
 /* Mask to determine which y pixels are valid in a pass */
 extern const uint8_t ff_png_pass_ymask[NB_PASSES];
 
-/* minimum x value */
-extern const uint8_t ff_png_pass_xmin[NB_PASSES];
-
-/* x shift to get row width */
-extern const uint8_t ff_png_pass_xshift[NB_PASSES];
-
 /* Mask to determine which pixels are valid in a pass */
 extern const uint8_t ff_png_pass_mask[NB_PASSES];