Eliminate the use of a staging buffer in WriteChars().
Fix [22c10c8e79]: core-8-5: msvc6 build: "Side by Side" error
Fix [4b3b7a3082]: tcl8.5.15/generic/tclExecute.c:7713: array index before sanity check ?
Fix [651e828a52]: Wrong Windows version reported for Windows 8.1
merge 8.5