This function accepts flags:

RB_NO_KEYWORDS, RB_PASS_KEYWORDS, RB_PASS_CALLED_KEYWORDS:
Works as the same as rb_block_call_kw.

RB_BLOCK_NO_USE_PACKED_ARGS:
The given block ("bl_proc") does not use "yielded_arg" of rb_block_call_func_t.
Instead, the block accesses the yielded arguments via "argc" and "argv".
This flag allows the called method to yield arguments without allocating an Array.

Must not be a bad idea to improve documents. [ci skip]

Truly editorial fix for comments.  This works better with Emacs'
set-justification-full function. [ci skip]

To get rid of a void function at the end of non-void function.

This is a pure refactoring that improves understanding of what is going
on.  Not a big win though.

To fix build failures.

Devs do not love "impl".