QuietLullaby

Hi, I am building the project from sources with cmake (should I use the source archive available on exiv2.org ?). I followed these instructions : ``` git clone https://github.com/Exiv2/exiv2.git #...

In fact, I was already linking to `lstdc++fs` with `-lstdc++fs` but I am using a cross compiler that is based on gcc 7.4.1 and doesn't know of std::filesystem but std::experimental::filesystem...