[SOLVED] fatal error: syncstream: No such file or directory

Issue

How do I install syncstream header?

gcc --version
gcc (Ubuntu 9.2.1-9ubuntu2) 9.2.1 20191008

Solution

The answer was given by Ted Lyngmo in a comment. To have a regular answer I copied it here:

You need to upgrade to at least g++ 11. Probably 11.1. Then including syncstream and compiling with g++ -std=c++20 ... works.`

Answered By - Ingo