configure: Drop stray extralibs for libspeex

These extralibs are set by pkg-config already.

configure

@@ -4760,7 +4760,7 @@ enabled libpulse          && require_pkg_config libpulse libpulse-simple pulse/s
 enabled librtmp           && require_pkg_config librtmp librtmp librtmp/rtmp.h RTMP_Socket
 enabled libschroedinger   && require_pkg_config libschroedinger schroedinger-1.0 schroedinger/schro.h schro_init
 enabled libsnappy         && require libsnappy snappy-c.h snappy_compress -lsnappy
-enabled libspeex          && require_pkg_config libspeex speex speex/speex.h speex_decoder_init -lspeex
+enabled libspeex          && require_pkg_config libspeex speex speex/speex.h speex_decoder_init
 enabled libtheora         && require libtheora theora/theoraenc.h th_info_init -ltheoraenc -ltheoradec -logg
 enabled libtwolame        && require libtwolame twolame.h twolame_init -ltwolame
 enabled libvo_aacenc      && require libvo_aacenc vo-aacenc/voAAC.h voGetAACEncAPI -lvo-aacenc