* libc/stdio/open_memstream.c (internal_open_memstream_r): Fix max
buffer size to be in wchar_t units if wide == 1 is passed in. In
this case, also initialize the first character of the buffer to be
wide char null.
(_open_wmemstream_r): Cast buf to be (char **) to avoid warning.
* libc/stdlib/mbtowc_r.c (_mbtowc_r): Change all occurences of
incrementing the size_t value n to first check that n is not already
size_t -1. Fix some compiler warnings.
* libc/stdlib/wcstod.c: Add includes for <wctype.h> and <math.h>.
(struct memstream): Add wide element.
Change saved to a union to take char and wchar_t values.
(memwriter): Accommodate wide-oriented oeprations.
(memseeker): Ditto.
(memseeker64): Ditto.
(memcloser): Ditto.
(internal_open_memstream_r): New static function. Take functionality
from former _open_memstream_r and handle additional "wide" parameter.
(_open_memstream_r): Just call internal_open_memstream_r with wide==-1
from here.
(_open_wmemstream_r): New function.
(open_wmemstream): Ditto.
* libc/include/wchar.h (open_wmemstream): Declare.
(_open_wmemstream_r): Declare.
Jeff Johnston
Kevin Buettner
Corinna Vinschen
Eric Blake