static_assert without message assumes C++17

[rhaensch]

Matplotlib docu says that C++11 is required. However, the current use of static_assert assumes C++17: https://en.cppreference.com/w/cpp/language/static_assert

[mdaley]

What's the chance of upgrading the project to require C++17? I'm keen on being able to do what I describe at the bottom of https://github.com/lava/matplotlib-cpp/issues/75 (although, that said, I could do it another way too that is C+11 compatible).

[Chachay]

I agree. At least, Makefile must be consistent

CXXFLAGS += -std=c++11 -Wno-conversion

[electriczity]

Can you simply add a debug message? Every time when I "git clone" this repo I must manually fix this problem. It is really boring.