Proposed fix for [2f7cbd01c3].
Fix [2f7cbd01c3]: tcl8.6.1 fails to build on FreeBSD 10.0
Fix [2f7cbd01c3]: tcl8.6.1 fails to build on FreeBSD 10.0
Added comments raising questions about possible updates to channel
drivers on Windows.
Implementation of [b42b208ba4]: file attributes -readonly on Cygwin. For completeness, implemented -archive, -hidden and -system as well.
Only write back file attributes if any of them really changed.
Implement RFE [b42b208ba4]: file attributes -readonly (and -archive, -hidden, -system) on Cygwin.
New test iortrans-4.8.1 exposes segfault bug [721ec69271].
Test iogt-2.4 is another segfault demo for [721ec69271].
Test iogt-2.4 is another segfault demo for [721ec69271].
Test iocmd-23.11 demos another segfault.
Test iocmd-23.11 demos another segfault.
Minimal patch to fix iocmd-23.11.  Might not be the best fix, but is *a* fix.
Merge minimal fix for iocmd-23.11.
Note that top channel regeneration is removed, so that Preserve/Release
call pairs are sure to operate on the same pointers.  Other bug fixes
may need to change that.
Better cookie option parsing that doesn't throw away critical information.
merge trunk