It turns out we no longer need the VSB at this point since it is
equivalent to the symbol's rname.

We don't need to since cache objects are mostly immutable and headers
are read-only in VCL.

Better diff with the --ignore-all-space option.

It is no longer supported in VCL, but strtod() will accept it.

Fixes #3971

If oc->boc is not NULL for an ObjFreeObj() call, the stevedore
needs to finish any busy object transaction.

Fixes #3953

Fixes #3952

ESI threads waiting for busy objects stopped looping in 2016
f839d558

This drastically reduces the number of printf-like operations.

Fixes #3968

And use it to implement ALLOC_FLEX_OBJ().

Even though the flexible array may start inside the padding, an array of
zero elements could then lead to less than sizeof bytes.

We lose the ability to check that fld is indeed the last field, but we
never had that ability to begin with.

We did mention it in the release docs, but not in changes.rst