Restore panic check at and of the loop. Thanks! Don for noticing this.
Backported [Bug 2882342]: correct struct _REPARSE_DATA_BUFFER  in tcl 8.4
merge-mark
Turn Tcl_PkgPresent/Tcl_PkgRequire into a macro. 
Make sure that extensions which are compiled using Tcl version 9.0 alpha/beta headers only run with the exact same Tcl version (9.0a0), so they cannot accidently be used in production. Idea 'stolen' from iTcl 4.0, which did that during alpha/beta
Dde/Registry: eliminate usage of some older API, which might be removed/deprecated in the future.
merge trunk
Remove TclWinNToHS, it is not used anywhere any more.
fix off-by-one error introduced in bd7d7a2061
tailcall now running in a simpler model, with no eval-flags and no nre-stack rewriting; yieldto also requires one fewer bounce. Mostly from mig-nre-mods
Name functions according to 'what' instead of 'how' in the [tailcall]
machinery, in view of making public some parts of it.
First attempt at fixing problems caused by [array set] inside [namespace eval],
which caused partial bytecode generation followed by a reject which triggered
the issuing of generic ensemble code with an extra push of the variable name at
the start (which got the stack depth wrong).
merge trunk
testing a cheaper(?) INST_START_COMMAND
Test for Bug 1884496 (not buggy on trunk).
fix for consecutive ISC (produced by [while 1 {...})
better comments
merge trunk
even better ... or so I hope: also inlining INST_PUSH1 in the peephole, checking for ISC after LOAD1 and PUSH1
discouraging the compiler from re-reading *pc in the peephole loop
discouraging the compiler from re-reading *pc in the peephole loop, part2 (any diff?)
Put back TclBackgroundException in internal stub table, so extensions using this, compiled against 8.5 headers still run in Tcl 8.6.