Before we accepted a nullable allocator for some stuff like
opening files. Now we require an allocator.
Use the mem.FixedBufferAllocator pattern if a bound on the amount
to allocate is known.
This also establishes the pattern that usually an allocator is the
first argument to a function (possibly after "self").
fix docs for std.cstr.addNullByte
self hosted compiler:
* only build docs when explicitly asked to
* clean up main
* stub out zig fmt
a2bd9f8912