As per the MCUXpresso IDE v10.0.0 User Guide, chapter 11, "C/C++ Library Support", Redlib is still a C90 standard C library (with a few C99 extensions). There are no plans to add C++ support to Redlib.
Generally for C++, use Newlib-Nano (which is what the IDE's SDK new project wizard will default to using). Otherwise, you can use Newlib.
Regards,
MCUXpresso IDE Support