- add inline function to test and convert surrogates
is_surrogate(c), is_hi_surrogate(c), is_lo_surrogate(c),
get_hi_surrogate(c), get_lo_surrogate(c), from_surrogate(hi, lo)
- use names for BC header offsets and lengths in libregexp.c
- remove strict aliasing violations in `lre_exec_backtrack()`
- pass all context variables to XXX_CHAR macros in `lre_exec_backtrack()`
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.
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()`
