Newlib 1.18.0 is released

[Jeff Johnston]

The latest snapshot is on the web-site.

Thanks to everyone who contributed.

*** Major changes in newlib version 1.18.0:

* wide-char enhancements
* long double math routines added for platforms where LDBL == DBL
* long long math routines added
* math cleanup
* UTF-16 modifications for Cygwin
* major locale charset overhaul including added charsets
* added moxie platform
* added rx platform
* added xc16x platform
* various cleanups
* various bug fixes