This had been forgotten in df81fa11.

Fixes #1711.

This requires bumping up to a minimum of CMake 3.1. The benefit
of using the imported target is that you can switch to the -pthread
compiler flag on request, which may be necessary for some systems if
available.

Replace std::map with std::array for graphics event breakpoints, and allow the compiler to inline. Saves 1%+ in vertex heavy situations.

- This is because we compile the full shader code space, and therefore its common to compile malformed instructions.