Fix [3118489]: NUL in filenames. (On Windows, protect against invalid use of ':' in filenames as well)
Minor bug-fix in [3118489] implementation: NUL in filenames. Filenames starting with <drive>: but without a following slash should be considered volume-relative i.e. the ':' is valid here.
Portable test to demo bug otherwise seen only on Windows.
Branch to demo bug introduced in the parent commit.
More tests to demo the bug more directly.
Bug fix - accept consumption of the trailing newline in crlf with no
characters produced.  Also delete false assertions.
Merge completion of dgp-read-bytes branch.
merge 8.5
Fix for failing tests *io-32.11*
merge 8.5
merge trunk