CMAKE_CXX_STANDARD is set to 14 but [[nodiscard]] is a C++17 feature

[patsp]

Hi, I noticed a minor inconsistency in the build.

In the CMakeLists.txt, CMAKE_CXX_STANDARD is set to 14:

TEASER-plusplus/CMakeLists.txt

Line 4 in 111e2ce

set(CMAKE_CXX_STANDARD 14)

But in graph.h, [[nodiscard]], which is a C++17 feature (https://en.cppreference.com/w/cpp/language/attributes/nodiscard), is used for example here:

TEASER-plusplus/teaser/include/teaser/graph.h

Line 131 in 111e2ce

[[nodiscard]] int numVertices() const { return adj_list_.size(); }

[jingnanshi]

Thanks for reporting this. I will likely remove [[nodiscard]] from the code.