Provide support for TIP 627 (Tcl 8.7a6+ and Tcl 9) TIP 627 introduces support for > 2^31 elements in object vectors (e.g., number of words in a single Tcl command). For details, see https://core.tcl-lang.org/tips/doc/trunk/tip/627.md
To provide also backwards compatibility, this change uses the macros TCL_COMMAND_OBJPROC, TCL_CREATEOBJCOMMAND, TCL_NRCALLOBJPROC, TCL_NRCREATECOMMAND, TCL_OBJCMDPROC_T, and TCL_OBJC_T.
Added support for compiling with Tcl 9.0 (Many Thanks to Jan Nijtmans for first steps) This version compiles cleanly at least with Tcl 8.6.* and Tcl 9.0 (fossil trunk), having -pedantic and -Wextra defined.