Bit of a fixup, missing imports.
Fixing the other pt tests to match the accumulated changes/bug-fixes
Tweaks to tests, to handle Tcl/C differences.
Fixes in the C runtime, known bugs fixed before in other places (COMPLETE processing, missing charclass control). Plus fix in the error message generation for range operator.
More testsuite updates to match pevious commits. Testsuite now passes in full.
Sync to main pt changes.