Switch to the OpenBSD wcsto* functions.

This replaces a partial set of non-functional functions with a complete
set of functions, all of which actually work.

This requires us to implement mbsnrtowcs and wcsnrtombs which completes
the set of what we need for libc++.

The mbsnrtowcs is basically a copy & paste of wcsnrtombs, but I'm going
to go straight to looking at using the OpenBSD UTF-8 implementation rather
than keep polishing our home-grown turd.

(This patch also opportunistically switches us over to upstream btowc,
mbrlen, and wctob, since they're all trivially expressed in terms of
other functions.)

Change-Id: I0f81443840de0f1aa73b96f0b51988976793a323
diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index 0029a65..12715c2 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -87,7 +87,8 @@
 extern int               mbsinit(const mbstate_t *);
 extern size_t            mbrlen(const char *, size_t, mbstate_t *);
 extern size_t            mbrtowc(wchar_t *, const char *, size_t, mbstate_t *);
-extern size_t            mbsrtowcs(wchar_t *, const char **, size_t, mbstate_t *);
+extern size_t mbsrtowcs(wchar_t*, const char**, size_t, mbstate_t*);
+extern size_t mbsnrtowcs(wchar_t*, const char**, size_t, size_t, mbstate_t*);
 extern size_t            mbstowcs(wchar_t *, const char *, size_t);
 extern wint_t            putwc(wchar_t, FILE *);
 extern wint_t            putwchar(wchar_t);
@@ -113,16 +114,20 @@
 extern wchar_t          *wcsncat(wchar_t *, const wchar_t *, size_t);
 extern int               wcsncmp(const wchar_t *, const wchar_t *, size_t);
 extern wchar_t          *wcsncpy(wchar_t *, const wchar_t *, size_t);
+extern size_t wcsnrtombs(char*, const wchar_t**, size_t, size_t, mbstate_t*);
 extern wchar_t          *wcspbrk(const wchar_t *, const wchar_t *);
 extern wchar_t          *wcsrchr(const wchar_t *, wchar_t);
-extern size_t            wcsrtombs(char *, const wchar_t **, size_t, mbstate_t *);
+extern size_t wcsrtombs(char*, const wchar_t**, size_t, mbstate_t*);
 extern size_t            wcsspn(const wchar_t *, const wchar_t *);
 extern wchar_t          *wcsstr(const wchar_t *, const wchar_t *);
-extern double            wcstod(const wchar_t *, wchar_t **);
-extern wchar_t          *wcstok(wchar_t *, const wchar_t *, wchar_t **);
-extern long int          wcstol(const wchar_t *, wchar_t **, int);
-extern size_t            wcstombs(char *, const wchar_t *, size_t);
-extern unsigned long int wcstoul(const wchar_t *, wchar_t **, int);
+extern double wcstod(const wchar_t*, wchar_t**);
+extern float wcstof(const wchar_t*, wchar_t**);
+extern wchar_t* wcstok(wchar_t*, const wchar_t*, wchar_t**);
+extern long wcstol(const wchar_t*, wchar_t**, int);
+extern long long wcstoll(const wchar_t*, wchar_t**, int);
+extern long double wcstold(const wchar_t*, wchar_t**);
+extern unsigned long wcstoul(const wchar_t*, wchar_t**, int);
+extern unsigned long long wcstoull(const wchar_t*, wchar_t**, int);
 extern wchar_t          *wcswcs(const wchar_t *, const wchar_t *);
 extern int               wcswidth(const wchar_t *, size_t);
 extern size_t            wcsxfrm(wchar_t *, const wchar_t *, size_t);