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
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
merge trunk
NRE now running on a stack! Version 0: more things to test and details to polish.