Existing call stack depth checks are unified into this check in
`cipush()`. The maximum depth is now specified by `MRB_CALL_LEVEL_MAX`
(the default is 512).  The older `MRB_FUNCALL_DEPTH_MAX` is no longer
used.

When the length operand is zero, we don't need `OP_MOVE` but adjust the
destination operand instead.

build(deps): bump github/super-linter from 4.8.0 to 4.8.1

The bug was introduced in 8be78bd.

Bumps [github/super-linter](https://github.com/github/super-linter) from 4.8.0 to 4.8.1.
- [Release notes](https://github.com/github/super-linter/releases)
- [Changelog](https://github.com/github/super-linter/blob/main/docs/release-process.md)
- [Commits](https://github.com/github/super-linter/compare/v4.8.0...v4.8.1)

---
updated-dependencies:
- dependency-name: github/super-linter
  dependency-type: direct:production
  update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>

Which represent `obj[int]` and `obj[int]=val` respectively where `obj`
is either `string`, `array` or `hash`, so that index access could be
faster. When `obj` is not assumed type or `R(a+1)` is not integer, the
instructions fallback to method calls.

Merge branch 'inline-struct-gem' of https://github.com/dearblue/mruby into dearblue-inline-struct-gem

- `mruby-binding-core` should be handle through dependency
- `mruby-inline-struct` is only for tests

build(deps): bump github/super-linter from 4.7.3 to 4.8.0

Bumps [github/super-linter](https://github.com/github/super-linter) from 4.7.3 to 4.8.0.
- [Release notes](https://github.com/github/super-linter/releases)
- [Changelog](https://github.com/github/super-linter/blob/master/docs/release-process.md)
- [Commits](https://github.com/github/super-linter/compare/v4.7.3...v4.8.0)

---
updated-dependencies:
- dependency-name: github/super-linter
  dependency-type: direct:production
  update-type: version-update:semver-minor
...
Signed-off-by: dependabot[bot] <support@github.com>

It used to be compiled to the static string in the compiler. But the
encoding status actually depends on the runtime configuration. A new
method `Kernel#__ENCODING__` is introduced to implement the feature.

Otherwise, the following code will crash:

```ruby
1.times{{}until 1; break}
```

Rename `MRB_WORDBOX_USE_HEAP_FLOAT` to `MRB_WORDBOX_NO_FLOAT_TRUNCATE'.

This reverts commit 913a0a5a.
In some cases, `OP_HASHADD` operand may not be `Hash`. We should check
explicitly in those cases.

In addition, add `NODE_SYM` for always true expression.

The invocation of `initialize` hook can cause infinite recursion too
easily. We stop invoking the method for safety, at the cost of less
flexibility.

The `initialize` methods (e.g. ones defined in `mrblib/10error.rb`) are
called only from `NoMethodError.new(args..)` forms.

`acc` meant `accumulator` but it is not an accumulator but just a
register position.

- `OP_ARYPUSH` now takes operand for the number of pushing elements
- the code generator consume the stack no more than `64` for `mruby/c`

Add n elements at once. Reduces instructions for huge array
initialization. In addition, `gen_value` function in `codegen.c` was
refactored and clarified.