Move some conditionally used variables into the block where they are used.

This allows dropping the av_unused argument from them.

libavformat/asfdec.c

@@ -365,8 +365,8 @@ static int asf_read_stream_properties(AVFormatContext *s, int64_t size)
         /* This code assumes that extradata contains only palette */
         /* This is true for all paletted codecs implemented in libavcodec */
         if (st->codec->extradata_size && (st->codec->bits_per_coded_sample <= 8)) {
-            int av_unused i;
 #if HAVE_BIGENDIAN
+            int i;
             for (i = 0; i < FFMIN(st->codec->extradata_size, AVPALETTE_SIZE)/4; i++)
                 asf_st->palette[i] = av_bswap32(((uint32_t*)st->codec->extradata)[i]);
 #else

libavformat/nsvdec.c

@@ -566,7 +566,6 @@ static int nsv_read_chunk(AVFormatContext *s, int fill_header)
     uint32_t vsize;
     uint16_t asize;
     uint16_t auxsize;
-    uint32_t av_unused auxtag;
 
     av_dlog(s, "%s(%d)\n", __FUNCTION__, fill_header);
 
@@ -596,6 +595,7 @@ 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;
         auxsize = avio_rl16(pb);
         auxtag = avio_rl32(pb);
         av_dlog(s, "NSV aux data: '%c%c%c%c', %d bytes\n",

libavutil/sha.c

@@ -181,7 +181,7 @@ static void sha256_transform(uint32_t *state, const uint8_t buffer[64])
 {
     unsigned int i, a, b, c, d, e, f, g, h;
     uint32_t block[64];
-    uint32_t T1, av_unused(T2);
+    uint32_t T1;
 
     a = state[0];
     b = state[1];
@@ -193,6 +193,7 @@ static void sha256_transform(uint32_t *state, const uint8_t buffer[64])
     h = state[7];
 #if CONFIG_SMALL
     for (i = 0; i < 64; i++) {
+        uint32_t T2;
         if (i < 16)
             T1 = blk0(i);
         else