dist/IO/IO.xs: Silence compiler warning

This variable is unused, doesn't need to be declared.
PATCH [perl #112244]

:crlf currently doesn't fall back on :pending the way :perlio
does when the unread data doesn't fit into its own buffer. Instead it
just rejects them. This patch resolves that.  Tests are coming in a
future commit

The committer added a cast to get it to compile on Win32, and silence a
gcc warning on Linux
re/charset.t: Make sure locale is loaded at compile time

TO BE FURNISHED
utf8_heavy.pl: Add 'use re "/aa"'

This would speed up compilation and execution by a trivial amount, but
makes sure that no regular expression even tries to compile in Unicode,
which could cause recursive invocation of this.  Before this construct
was invented, special care had to be taken to keep that from happening;
those measures remain in effect, but this gives added insurance.
Some tests for [perl #112244]

Leon Timmermans is short of tuits right now, so I added these tests for
his patch.  Since I don't really know what I'm doing here, other tests
should eventually be added by someone who does know.
PATCH: [perl #116322]: getc() and ungetc() with unicode failure

ungetc() had no knowledge of UTF-8.  This patch adds it.

The committer fleshed out the author's code to make a patch, making
a few small changes.
Tests for [perl #116322]