#1835 namespace / trace double-free crash

[Jeffrey Hobbs]

The following code creates a double-free situation in
Tcl 8.3.4/8.4a4:

namespace eval ::foo {
variable x 123
}
proc p1 args {
trace vdelete ::foo::x u p1
}
trace variable ::foo::x u p1
namespace delete ::foo

I've correct this with the attached patch for 8.3.4
(and am applying a similar patch for 8.4a4).

[Jeffrey Hobbs]

[Jeffrey Hobbs]

8.4a4 version of patch attached,

[Jeffrey Hobbs]

Logged In: YES
user_id=72656

patches attached and commited.