aac: add headers needed for log2f()

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/aaccoder.c

@@ -36,6 +36,7 @@
 #include "aac.h"
 #include "aacenc.h"
 #include "aactab.h"
+#include "libavutil/libm.h"
 
 /** bits needed to code codebook run value for long windows */
 static const uint8_t run_value_bits_long[64] = {

libavcodec/aacsbr.c

@@ -32,6 +32,7 @@
 #include "aacsbrdata.h"
 #include "fft.h"
 #include "aacps.h"
+#include "libavutil/libm.h"
 
 #include <stdint.h>
 #include <float.h>