Various bits of cleanup, efficiencies, and comment documentation in tclVar.c
proposed fix for Bug 3598300
suggested fix for Bug 3092089: [file normalize] can remove path component, 
and for Bug 3587096: startup error message when exe in folder with junction with limited rights
Don't call "ulimit" on cygwin: On Cygwin the stack size cannot be modified, and the reported stacksize is much lower than the real one.
Extend the public and private stub tables with dummy NULL entries, up to the size of the Tcl 8.6 stub tables. 
This makes it easier to debug extensions which use Tcl 8.5/8.6 features but (erroneously) are attempted to be loaded in Tcl 8.4.
Extend the public stub table with dummy NULL entries, up to the size of the Tcl 8.6 stub tables. 
This makes it easier to debug extensions which use Tcl 8.6 features but (erroneously) are attempted to be loaded in Tcl 8.5.
merge-mark. Hoping trunk is OK now, again ;-(
Restrict the stub library to only use Tcl_PkgRequireEx, Tcl_ResetResult	and Tcl_AppendResult, not any other function. 
This puts least restrictions on eventual Tcl 9 stubs re-organization, and it works on the widest range of Tcl versions.
mSys doesn't have $PWD. Reported by Rene Zaumseil on Tcl Core list
new attempt for better fix
[Bug 3092089]: [file normalize] can remove path	components.
[Bug 3587096] win vista/7: "can't find init.tcl" when called via junction.
[Bug 3092089]: [file normalize] can remove path	components.
[Bug 3587096] win vista/7: "can't find init.tcl" when called via junction.
[Bug 3092089]: [file normalize] can remove path components.
[Bug 3587096] win vista/7: "can't find init.tcl" when called via junction.
$builddir is a local variable
[Bug 3599395]: http assumes status line is a proper tcl list. 
Bump http package to 2.7.11.
[Bug 3599395]: http assumes status line is a proper tcl list.
Backported [Bug 2882342]: correct struct _REPARSE_DATA_BUFFER  in tcl 8.4
merge-mark
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