* Fix big endian serialization
Big endian serialization was broken because:
- it partially relied on `WORDS_ENDIAN` (unconditionally undef'd in cutils.h)
- endianness was not handled at all in the bc reader.
- `bc_tag_str` was missing the `"RegExp"` string
- `lre_byte_swap()` was broken for `REOP_range` and `REOP_range32`
Modifications:
- remove `WORDS_ENDIAN`
- use `bc_put_u32()` / `bc_put_u64()` in `JS_WriteBigInt()`
- use `bc_get_u32()` / `bc_get_u64()` in `JS_ReadBigInt()`
- handle host endianness in `bc_get_u16()`, `bc_get_u32()`, `bc_get_u64()` and
`JS_ReadFunctionBytecode()`
- handle optional littleEndian argument as specified in
`js_dataview_getValue()` and `js_dataview_setValue()`
- fix `bc_tag_str` and `lre_byte_swap()`
There was no definition of the macro for compilers that were not gcc,
clang or msvc. While it would be easy to add one, a better approach is
to switch to memcpy() and avoid type punning altogether.
Fixes: https://github.com/quickjs-ng/quickjs/issues/270
