“C and C++ code targeting non-8-bit byte are incompatible dialects of C and C++.”
GCC, LLVM and MSVC all set CHAR_BIT to 8. POSIX has required 8-bit bytes since 2001, and GCC dropped dsp16xx in 2004 and 1750a in 2002. The C++ committee is being asked to ratify what every shipping compiler already does. Standards bodies move slower than the hardware they describe.