Merge pull request #5217 from shuujii/call-super-before-creating-host-build-in-MRubyCrossBuild-initialize

Call `super` before creating `host` build in `MRuby::CrossBuild#initialize`

Call `super` (`block`) ahead so that creation of the `host` build can be
skipped if pre-built `mrbc` can be specified in the future.

close #5213.

Allow obsoluted `MRB_METHOD_T_STRUCT`

Remove unused `@endian` in `MRuby::CrossBuild#initialize`

Update "Configuration Options Changed" in `doc/mruby3.md` [ci skip]

Make it possible that `libmruby.a` is not created

Previously, `libmruby.a` was created even if only `mruby-bin-mrbc` or`
mruby-compiler` was specified for gem, but by specifying `disable_libmruby`,
the creation of `libmruby.a` can be suppressed.

### Note

The https://github.com/mruby/mruby/pull/5084#issuecomment-723521971
incompatibility seems to be difficult for users to avoid, so the original
behavior has been restored. Therefore, if we need `mrbc` other than the
`host` build, we need to explicitly specify `mruby-bin-mrbc` gem.

Due to the above changes, `build_config/boxing.rb` etc. will not work, but I
have added` mruby-bin-mrbc` to `default.gembox` to fix it. I don't think
this change is a big deal because originally `mruby-compiler` was included.

Adjust insertion point in `fix_prepend_module()`.

Module#include and Module#prepend now affect classes and modules
that have already included or prepended the receiver, mirroring the
behavior if the arguments were included in the receiver before
the other modules and classes included or prepended the receiver.

```ruby
class C; end
module M1; end
module M2; end
C.include M1
M1.include M2
p C.ancestors #=> [C, M1, M2, Object, Kernel, BasicObject]
```

Move `mrbc` test to `mruby-bin-mrbc` gem from `mruby-compiler` gem

Remove `build/presym{,.inc}` by `rake clean` [ci skip]

Currently, adding gems to build configuration and rebuilding does not
regenerate `presym`, which can lead to build errors.

Therefore in this case we need to remove the `presym` file and then rebuild
mruby, but when the` presym` file is regenerated we will need to recompile
most of the files, so it seems useful to have the `presym` file deleted by
`rake clean`.

Fix build for C++ version >= C++11 when `enable_cxx_exception`; close #5199

Remove unused Rake rules

Revert "Create presym files for each build target" (58ba883e)

Due to the above changes, it may not work with the existing build
configurations in cross-compilation (even if we can build without presym),
therefore revert it once (ref https://github.com/mruby/mruby/pull/5202#issuecomment-735412643). Sorry for the lack of consideration.

Improves dump irep

Fixed print catch handler address in codedump; ref #5200

Alleviates confusingness.

ref #5203

It became 32 bits in #5200, but only the upper 16 bits were printed.

Use `MRB_SYM` in `src/gc.c`

Fix heap buffer overflow when dump irep

Currently, the size of writing in heap by write_irep_record() is
bigger than The size that is calculated by get_irep_record_size.

Therefore, irep is dumped over the size of allocating memory when we
execute dump_irep().

Change the catch handler address to 32 bits

Follow commit 7150c675 .