merge trunk
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
Insure that PURIFY builds cannot exploit the Tcl stack to hide mem defects.
Add super-simple compiler to many ensemble subcommands to allow better code
generation where we can detect that we're not in the WrongNumArgs case.
The compiler just checks that the argument count is in the right range and
issues a standard dispatch; that's enough to do an efficient job.
Improve code generation for many simple core ensemble subcommands.
Fix bad memory access problems found by Miguel Sofer when valgrinding.
Fix memory leak in [format] compiler.
Add an assertion that checks the stack depth under TCL_COMPILE_DEBUG *before* stack cleanup. It currently triggers at several spots in the testsuite!
adjust stub library version number
adjust stub library version number
adjust stub library version number
fix the new assertion, it should not trigger when an expansion is in progress
merge fork
improved stack checking under TCL_COMPILE_DEBUG
Don't depend on Spencer-specific regexp syntax (/u and /U) any more in unrelated places
.  Bump http package to 2.8.6.
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.