This matters when there are multiple man page windows open.

Problems:
    - Scope of local variables in options code is too large.
    - did_set_string_option() is too large (>1000LOC).
    - Setting options for a particular window or buffer requires a changing context (assigning curwin/curbuf).

Solutions:
    - Reduce the scope of local variables.
    - Break up did_set_string_option so it doesn't contain specific logic about each individual option (1038 LOC -> 310 LOC).
    - Begin work on making functions not depend on curbuf or curwin and pass window or buffer handles explicitly.

There are a number of cmake variables and cache variables that need to
be passed to all dependencies. This is not only cumbersome, but also
fragile as it's easy to miss adding or removing a flag from a dependency
by accident. Introducing a global variable that controls all builds
makes it much easier to handle our dependencies.

Also fixes the currently broken release workflow as we need to pass the
CMAKE_OSX_ARCHITECTURES variable to all dependencies built with cmake.