Give names of external library decoders/encoders a lib prefix

in the ffmpeg/ffplay output.

Originally committed as revision 9227 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/liba52.c

@@ -248,7 +248,7 @@ static int a52_decode_end(AVCodecContext *avctx)
 }
 
 AVCodec liba52_decoder = {
-    "ac3",
+    "liba52",
     CODEC_TYPE_AUDIO,
     CODEC_ID_AC3,
     sizeof(AC3DecodeState),

libavcodec/libgsm.c

@@ -84,7 +84,7 @@ static int libgsm_encode_frame(AVCodecContext *avctx,
 
 
 AVCodec libgsm_encoder = {
-    "gsm",
+    "libgsm",
     CODEC_TYPE_AUDIO,
     CODEC_ID_GSM,
     0,
@@ -94,7 +94,7 @@ AVCodec libgsm_encoder = {
 };
 
 AVCodec libgsm_ms_encoder = {
-    "gsm",
+    "libgsm_ms",
     CODEC_TYPE_AUDIO,
     CODEC_ID_GSM_MS,
     0,
@@ -123,7 +123,7 @@ static int libgsm_decode_frame(AVCodecContext *avctx,
 }
 
 AVCodec libgsm_decoder = {
-    "gsm",
+    "libgsm",
     CODEC_TYPE_AUDIO,
     CODEC_ID_GSM,
     0,
@@ -134,7 +134,7 @@ AVCodec libgsm_decoder = {
 };
 
 AVCodec libgsm_ms_decoder = {
-    "gsm_ms",
+    "libgsm_ms",
     CODEC_TYPE_AUDIO,
     CODEC_ID_GSM_MS,
     0,