aacenc: add AAC_CODER_NB

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/aaccoder.c

@@ -1112,7 +1112,7 @@ static void search_for_ms(AACEncContext *s, ChannelElement *cpe,
     }
 }
 
-AACCoefficientsEncoder ff_aac_coders[] = {
+AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
     {
         search_for_quantizers_faac,
         encode_window_bands_info,

libavcodec/aacenc.h

@@ -30,6 +30,8 @@
 
 #include "psymodel.h"
 
+#define AAC_CODER_NB 4
+
 typedef struct AACEncOptions {
     int stereo_mode;
 } AACEncOptions;