Mark a number of variables only used in av_dlog() calls as av_unused.

This fixes a number of unused-but-set gcc warnings.

libavcodec/wmalosslessdec.c

@@ -22,6 +22,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "libavutil/attributes.h"
 #include "avcodec.h"
 #include "internal.h"
 #include "get_bits.h"
@@ -1041,7 +1042,7 @@ static int decode_frame(WmallDecodeCtx *s)
     /* no idea what these are for, might be the number of samples
        that need to be skipped at the beginning or end of a stream */
     if (get_bits1(gb)) {
-        int skip;
+        int av_unused skip;
 
         /* usually true for the first frame */
         if (get_bits1(gb)) {

libavformat/mov.c

@@ -25,6 +25,7 @@
 //#define DEBUG
 //#define MOV_EXPORT_ALL_METADATA
 
+#include "libavutil/attributes.h"
 #include "libavutil/audioconvert.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/intfloat.h"
@@ -596,8 +597,9 @@ static int mov_read_dec3(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 static int mov_read_chan(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     AVStream *st;
-    uint8_t version;
+    uint8_t av_unused version;
-    uint32_t flags, layout_tag, bitmap, num_descr, label_mask;
+    uint32_t av_unused flags;
+    uint32_t layout_tag, bitmap, num_descr, label_mask;
     int i;
 
     if (c->fc->nb_streams < 1)

libavformat/nsvdec.c

@@ -19,6 +19,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "libavutil/attributes.h"
 #include "libavutil/mathematics.h"
 #include "avformat.h"
 #include "internal.h"
@@ -273,7 +274,7 @@ static int nsv_parse_NSVf_header(AVFormatContext *s)
 {
     NSVContext *nsv = s->priv_data;
     AVIOContext *pb = s->pb;
-    unsigned int file_size;
+    unsigned int av_unused file_size;
     unsigned int size;
     int64_t duration;
     int strings_size;
@@ -595,7 +596,7 @@ null_chunk_retry:
     av_dlog(s, "NSV CHUNK %d aux, %u bytes video, %d bytes audio\n", auxcount, vsize, asize);
     /* skip aux stuff */
     for (i = 0; i < auxcount; i++) {
-        uint32_t auxtag;
+        uint32_t av_unused auxtag;
         auxsize = avio_rl16(pb);
         auxtag = avio_rl32(pb);
         av_dlog(s, "NSV aux data: '%c%c%c%c', %d bytes\n",