`--static` is no longer an option. Instead, Zig makes things as static
as possible by default. `-dynamic` can be used to choose a dynamic
library rather than a static one.

`--enable-pic` is a new option. Usually it will be enabled
automatically, but in the case of build-exe with no dynamic libraries
on Linux or freestanding, Zig chooses off by default.

closes #1703
closes #1828