libavcodec/flacenc: Implement encoding of 32 bit-per-sample PCM

Add encoding of 32 bit-per-sample PCM to FLAC files to libavcodec.
Coding to this format is at this point considered experimental and
-strict experimental is needed to get ffmpeg to encode such files.

libavcodec/put_bits.h

@@ -363,6 +363,13 @@ static inline void put_bits64(PutBitContext *s, int n, uint64_t value)
     }
 }
 
+static inline void put_sbits63(PutBitContext *pb, int n, int64_t value)
+{
+    av_assert2(n >= 0 && n < 64);
+
+    put_bits64(pb, n, (uint64_t)(value) & (~(UINT64_MAX << n)));
+}
+
 /**
  * Return the pointer to the byte where the bitstream writer will put
  * the next bit.

libavcodec/put_golomb.h

@@ -151,18 +151,4 @@ static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit,
     set_ur_golomb(pb, v, k, limit, esc_len);
 }
 
-/**
- * write signed golomb rice code (flac).
- */
-static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k,
-                                      int limit, int esc_len)
-{
-    int v;
-
-    v  = -2 * i - 1;
-    v ^= (v >> 31);
-
-    set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
-}
-
 #endif /* AVCODEC_PUT_GOLOMB_H */