* time/time.h (struct timespec): Use __time_t for tv_sec element.
* sysdeps/generic/inttypes.h: Define __wchar_t. Use it instead of
wchar_t for function declarations and defintions.
* misc/sys/select.h: Define __need_time_t before including <time.h>.
Define suseconds_t if it hasn't happened yet.
* iconv/gconv.h: Define __need_wchar_t before including <stddef.h>.
* conform/data/sys/uio.h-data: Allow UIO_MAXIOV to be defined.
* sysdeps/generic/stdint.h: Don't get definition of wchar_t from
<stddef.h>.
* conform/data/stddef.h-data: Remove wint_t.