LinuxQuestions.org - sox compile error on gentoo

i was emerging gentoo and whgen i get to sox this is what i get.

alsa.c:145: error: dereferencing pointer to incomplete type
alsa.c:145: error: parse error before "snd_pcm_access_t"
alsa.c:146: error: dereferencing pointer to incomplete type
alsa.c:147: error: dereferencing pointer to incomplete type
alsa.c:149: error: parse error before "snd_pcm_hw_param_t"
alsa.c:150: error: dereferencing pointer to incomplete type
alsa.c:150: error: parse error before "snd_pcm_hw_param_t"
alsa.c:151: error: dereferencing pointer to incomplete type
alsa.c:152: error: dereferencing pointer to incomplete type
alsa.c:153: error: dereferencing pointer to incomplete type
alsa.c:155: error: parse error before "snd_pcm_hw_param_t"
alsa.c:156: error: dereferencing pointer to incomplete type
alsa.c:156: error: parse error before "snd_pcm_hw_param_t"
alsa.c:157: error: dereferencing pointer to incomplete type
alsa.c:158: error: dereferencing pointer to incomplete type
alsa.c:158: error: dereferencing pointer to incomplete type
alsa.c:159: error: dereferencing pointer to incomplete type
alsa.c:159: error: dereferencing pointer to incomplete type
alsa.c:160: error: dereferencing pointer to incomplete type
alsa.c:161: error: dereferencing pointer to incomplete type
alsa.c:162: error: dereferencing pointer to incomplete type
alsa.c:164: error: parse error before "snd_pcm_hw_param_t"
alsa.c:165: error: dereferencing pointer to incomplete type
alsa.c:165: error: parse error before "snd_pcm_hw_param_t"
alsa.c:166: error: dereferencing pointer to incomplete type
alsa.c:167: error: dereferencing pointer to incomplete type
alsa.c:167: error: dereferencing pointer to incomplete type
alsa.c:168: error: dereferencing pointer to incomplete type
alsa.c:168: error: dereferencing pointer to incomplete type
alsa.c:169: error: dereferencing pointer to incomplete type
alsa.c:170: error: dereferencing pointer to incomplete type
alsa.c:171: error: dereferencing pointer to incomplete type
alsa.c:173: error: parse error before "snd_pcm_hw_param_t"
alsa.c:174: error: dereferencing pointer to incomplete type
alsa.c:174: error: parse error before "snd_pcm_hw_param_t"
alsa.c:175: error: dereferencing pointer to incomplete type
alsa.c:176: error: dereferencing pointer to incomplete type
alsa.c:176: error: dereferencing pointer to incomplete type
alsa.c:177: error: dereferencing pointer to incomplete type
alsa.c:177: error: dereferencing pointer to incomplete type
alsa.c:178: error: dereferencing pointer to incomplete type
alsa.c:179: error: dereferencing pointer to incomplete type
alsa.c:180: error: dereferencing pointer to incomplete type
alsa.c:182: error: parse error before "snd_pcm_hw_param_t"
alsa.c:183: error: dereferencing pointer to incomplete type
alsa.c:183: error: parse error before "snd_pcm_hw_param_t"
alsa.c:184: error: dereferencing pointer to incomplete type
alsa.c:185: error: dereferencing pointer to incomplete type
alsa.c:185: error: dereferencing pointer to incomplete type
alsa.c:186: error: dereferencing pointer to incomplete type
alsa.c:186: error: dereferencing pointer to incomplete type
alsa.c:187: error: dereferencing pointer to incomplete type
alsa.c:188: error: dereferencing pointer to incomplete type
alsa.c:189: error: dereferencing pointer to incomplete type
alsa.c:191: error: parse error before "snd_pcm_hw_param_t"
alsa.c:192: error: dereferencing pointer to incomplete type
alsa.c:192: error: parse error before "snd_pcm_hw_param_t"
alsa.c:193: error: dereferencing pointer to incomplete type
alsa.c:194: error: dereferencing pointer to incomplete type
alsa.c:194: error: dereferencing pointer to incomplete type
alsa.c:195: error: dereferencing pointer to incomplete type
alsa.c:195: error: dereferencing pointer to incomplete type
alsa.c:196: error: dereferencing pointer to incomplete type
alsa.c:197: error: dereferencing pointer to incomplete type
alsa.c:198: error: dereferencing pointer to incomplete type
alsa.c: In function `st_alsastartread':
alsa.c:222: error: storage size of 'params' isn't known
alsa.c:222: warning: unused variable `params'
alsa.c: In function `st_alsastartwrite':
alsa.c:273: error: storage size of 'params' isn't known
alsa.c:273: warning: unused variable `params'
alsa.c: In function `get_format':
alsa.c:602: error: parse error before "snd_pcm_format_t"
alsa.c:602: error: parse error before "snd_pcm_format_t"
alsa.c:610: error: `SNDRV_PCM_FORMAT_U16' undeclared (first use in this function )
alsa.c:610: error: (Each undeclared identifier is reported only once
alsa.c:610: error: for each function it appears in.)
alsa.c:610: error: `SNDRV_PCM_FORMAT_S16' undeclared (first use in this function )
alsa.c:637: error: parse error before "snd_pcm_format_t"
alsa.c:644: error: parse error before "snd_pcm_format_t"
alsa.c:651: error: parse error before "snd_pcm_format_t"
alsa.c:667: error: parse error before "snd_pcm_format_t"
alsa.c:671: error: parse error before "snd_pcm_format_t"
alsa.c:674: error: parse error before "snd_pcm_format_t"
alsa.c:678: error: parse error before "snd_pcm_format_t"
make[1]: *** [alsa.o] Error 1
make[1]: Leaving directory `/var/tmp/portage/sox-12.17.7-r2/work/sox-12.17.7/src '
make: *** [all] Error 2

!!! ERROR: media-sound/sox-12.17.7-r2 failed.
!!! Function src_compile, Line 51, Exitcode 2
!!! make failed
!!! If you need support, post the topmost build error, NOT this status message.

this is the last part of it.