Fixes compilation with --disable-encoders --enable-encoder=aac
# decoders / encoders
aac_decoder_select="imdct15 mdct sinewin"
aac_fixed_decoder_select="mdct sinewin"
-aac_encoder_select="audio_frame_queue iirfilter mdct sinewin"
+aac_encoder_select="audio_frame_queue iirfilter lpc mdct sinewin"
aac_latm_decoder_select="aac_decoder aac_latm_parser"
ac3_decoder_select="ac3_parser ac3dsp bswapdsp fmtconvert mdct"
ac3_fixed_decoder_select="ac3_parser ac3dsp bswapdsp mdct"