Compile Error at g++ 7.3 / ubuntu 18.04

[kckjn97]

In Ubuntu 16.04 and g++ 5.4, I could compile FlashX normally.
But, I could not compile FlashX. I use ubuntu latest version(18.04) and g++(7.3).
I see below error.

/home/kckjn97/flashx/matrix/data_io.cpp:278:17: error: could not convert ‘std::unique_ptr<char []>()’ from ‘std::unique_ptr<char []>’ to ‘std::shared_ptr’
return std::unique_ptr<char[]>();