- Update _mbclen, mblen, _mbslen, _mbsnextc and _mbstrlen which should rely on the leadbyte mechanism

- Fixes 9 msvcrt string tests, 7 failures tbd
- Remove leftover function declaration from ismblead.c

svn path=/trunk/; revision=38181

reactos/lib/sdk/crt/mbstring/ismblead.c

@@ -14,8 +14,6 @@
 #include <precomp.h>
 #include <mbctype.h>
 
-size_t _mbclen2(const unsigned int s);
-
 /*
  * @implemented
  */