Adjust to the optimum type

Sprintf refactor

Raise argument error with the better message, at the only place
where the size to fill can be negative.

Instead of loop or `memcpy` after `CHECK`, use dedicated macros,
`FILL` and `PUSH`, respectively.

Add macOS support to mrb_ro_data_p

This adds macOS support to mrb_ro_data_p, fixes #3636

Restore 32-bit OSX builds

ref #3492 #3515 #3517

This reverts commit d2cad9ac.

To avoid redundant `mark_context()`.

This reverts commit a1d32af9.

Fix space flag with inf/nan

Fix embedded document with unterminated terminator

`skips()` is `mrb_bool` function, should return `FALSE` at EOF, not
`EOF`.

As for non-finite float, calculate the exact needed size with the
space flag.

While `"% 2f"` and `"% 4f"` result in `" Inf"` and `" Inf"`
respectively, `"% 3f"` results in `"Inf"` (no space).

Add --libmruby-path support to mruby-bin-mruby-config.

Reopens #3612.

Reopens #3550. Those 2 issues are exclusive.

Support `freeze` method in `Struct`.

Fix typo in usage message.

Align pool allocator with 8 byte in 64-bit environment.

Add missing `arg_i++` to fix bug of `s!` in mrb_get_args.