libunistring-dev binary package in Ubuntu Xenial amd64

 The 'libunistring' library implements Unicode strings (in the UTF-8,
 UTF-16, and UTF-32 encodings), together with functions for Unicode
 characters (character names, classifications, properties) and
 functions for string processing (formatted output, width, word
 breaks, line breaks, normalization, case folding, regular
 expressions).
 .
 This package contains the development support files needed to compile
 and link against libunistring, as well as the documentation in Info
 and HTML format.

Source package