Const vs static

A proposal to extend statics/constants so that `static` always declares a global variable (memory location) with an address and `const` declares global *values*. `const` is what we expect users to use most of the time, `static` is only intended to be used in narrow circumstances.
The address being insignificant only means that converting it to an integer and performing comparisons isn't meaningful. A constant can be inlined *without* giving it an insignificant address by using `available_externally` and a mutable global can be given an insignificant address without breaking anything.