Rename read/write_line() to av_read/write_image_line().

The old names were not av_ prefixed, and they were causing linking
failure on many platforms.  The new names are also more descriptive.

Patch by Stefano Sabatini.

Originally committed as revision 24101 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/vf_pixdesctest.c

@@ -90,13 +90,13 @@ static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
         int y1 = c == 1 || c == 2 ? y>>priv->pix_desc->log2_chroma_h : y;
 
         for (i = y1; i < y1 + h1; i++) {
-            read_line(priv->line,
+            av_read_image_line(priv->line,
                       inpic->data,
                       inpic->linesize,
                       priv->pix_desc,
                       0, i, c, w1, 0);
 
-            write_line(priv->line,
+            av_write_image_line(priv->line,
                        outpic->data,
                        outpic->linesize,
                        priv->pix_desc,

libavutil/pixdesc.c

@@ -24,7 +24,7 @@
 
 #include "intreadwrite.h"
 
-void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
+void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
                const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component)
 {
     AVComponentDescriptor comp= desc->comp[c];
@@ -65,7 +65,7 @@ void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
     }
 }
 
-void write_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
+void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
                 const AVPixFmtDescriptor *desc, int x, int y, int c, int w)
 {
     AVComponentDescriptor comp = desc->comp[c];

libavutil/pixdesc.h

@@ -108,7 +108,7 @@ extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
  * component c in data[1] to dst, rather than the palette indexes in
  * data[0]. The behavior is undefined if the format is not paletted.
  */
-void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
+void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
                const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
 
 /**
@@ -125,7 +125,7 @@ void read_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
  * @param w the width of the line to write, that is the number of
  * values to write to the image line
  */
-void write_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
+void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
                 const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
 
 /**