Make is_static_any variables inline

[MakoEnergy]

This is currently not possible because we are compiling for C++14, which does not support inline variables. When we upgrade to C++17 we should make is_static_any_v and is_static_any_decayed_v inline.

[MakoEnergy]

After attempting to make this change, it works on all platforms except Clang on Ubuntu using the official clang package. This appears to be an issue with the compiler itself as a similar version of clang on godbolt.org worked fine. Going to shelve inline variables for now, hoping that future releases will fix this without any intervention from us.