Do not use std::unary_function removed in C++17 (#10)
Do not use std::unary_function removed in C++17 (#10)

Authored-by: Jorge Lodos Vigil <d948c73101c8535fb6bdb6b5cac3a04f36e89d85@teradici.com>
ANSAKsoftware/ansak-string,ANSAKsoftware/ansak-string