Revert "configure: link flite against libasound"

This reverts commit 396648cc6a.

The commit made impossible to build against libflite if libasound is not
available (e.g. on Windows). Thus remove the -lasound flag. In case of
libflite static linking the workaround is to enable
--extra-ldflags=-lasound (or disable the ALSA output device in libflite).

configure

@@ -3653,7 +3653,7 @@ enabled libcelt    && require libcelt celt/celt.h celt_decode -lcelt0 &&
 enabled libcaca    && require_pkg_config caca caca.h caca_create_canvas
 enabled libfaac    && require2 libfaac "stdint.h faac.h" faacEncGetVersion -lfaac
 enabled libfdk_aac && require  libfdk_aac fdk-aac/aacenc_lib.h aacEncOpen -lfdk-aac
-flite_libs="-lflite_cmu_time_awb -lflite_cmu_us_awb -lflite_cmu_us_kal -lflite_cmu_us_kal16 -lflite_cmu_us_rms -lflite_cmu_us_slt -lflite_usenglish -lflite_cmulex -lflite -lasound"
+flite_libs="-lflite_cmu_time_awb -lflite_cmu_us_awb -lflite_cmu_us_kal -lflite_cmu_us_kal16 -lflite_cmu_us_rms -lflite_cmu_us_slt -lflite_usenglish -lflite_cmulex -lflite"
 enabled libflite   && require2 libflite "flite/flite.h" flite_init $flite_libs
 enabled libfreetype && require_pkg_config freetype2 "ft2build.h freetype/freetype.h" FT_Init_FreeType
 enabled libgsm     && require  libgsm gsm/gsm.h gsm_create -lgsm