Start working on [3389978]. Appears to work, but some clean-up needed.
More efficient/robust implementation of function TclNativeCreateNativeRep(). 
- No more intermediate results in a Tcl_DString, just allocate space directly. 
- Let MultiByteToWideChar() do all the difficult work, inclusive checking for invalid byte sequences.
- Handled extended win32 paths, inclusive UNC paths.
Implementation for a great deal taken over from fossil.
Make Cygwin's "configure" work from another directory than /unix. (Not everything works this way!)
Make Cygwin's "configure" work from another directory than /unix. (Not everything works this way!)
Fix [3389978]: Support for paths longer than MAX_PATH on Windows.
Test iocmd-32.1 is not "impossible" but after writing it properly it
does segfault trying to use a deleted interp.  Fixed.
Test iocmd-32.1 is not "impossible" but after writing it properly it does segfault trying to use a deleted interp. Fixed.
Tests (chan)io-34.21 are constrained for largefileSupport, and that's
disabled by default, which means never tested, which means the ridiculous
bugs in them are never found and fixed.

Fixed the bugs, changed the default.  Large File Suppport (4GB) is
commonplace now.  Let those without it suffer a few failing tests reporting
that fact to them.
Tests (chan)io-34.21 are constrained for largefileSupport, and that's disabled by default, which means never tested, which means the ridiculous bugs in them are never found and fixed.

Fixed the bugs, changed the default. Large File Suppport (4GB) is commonplace now. Let those without it suffer a few failing tests reporting that fact to them.
Added comment explaining the "knownBug" in iogt-6.1
Added comment explaining the "knownBug" in iogt-6.1
Correct namespace bugs in normally skipped tests.
Constrain them as "knownBug" rather than "unknownFailure".
Correct namespace bugs in normally skipped tests. Constrain them as "knownBug" rather than "unknownFailure".
Repair another "impossible" test and the segfault it reveals.
[6d2f249a01] Handle a failure to ccomprehend half-way through the compilation of a chain of compileable ensembles.
Have the [chan push] machinery ReadRaw() directly into the argument to be
passed to the read method of the channel transformation command.  Save a copy.
Restore the largefileSupport constraint on Darwin, where tests (chan)io-34.21
take an unbearable 90 seconds each to complete.
Restore the largefileSupport constraint on Darwin, where tests (chan)io-34.21
take an unbearable 90 seconds each to complete.
[958bc05fbe]: Clarify "clock format" using "%R"
[958bc05fbe]: Clarify "clock format" using "%R"