new modules utf8-ucs4-safe, utf16-ucs4-safe

[Bruno Haible]

The parsing primitives for UTF-8 and UTF-16 strings have optional
(compile-time configurable) safety checks. For some purposes, variants with
the safety checks always compiled in are needed. Here they are.

2006-12-25  Bruno Haible  <address@hidden>

        * modules/utf8-ucs4-safe: New file.
        * lib/utf8-ucs4-safe.h: New file.
        * lib/unistr/utf8-ucs4-safe.c: New file.

        * modules/utf16-ucs4-safe: New file.
        * lib/utf16-ucs4-safe.h: New file.
        * lib/unistr/utf16-ucs4-safe.c: New file.