* debug/wcstombs_chk.c: New file.
* debug/Makefile (routines): Add mbstowcs_chk and wcstombs_chk.
* debug/Versions: Add __mbstowcs_chk and __wcstombs_chk.
* stdlib/bits/stdlib.h: Add definitions for mbstowcs and wcstombs.
* wcsmbs/bits/wchar2.h (mbsrtowcs): Pretty printing.
* string/test-memset.c (test_main): Use negative byte value in