emitglue: Typo fix in var name.
showbc: MAKE_CLOSURE*: Update for new closed-over encoding.
windows/README: Use CROSS_COMPILE instead of CC to cover other tools too.

Suggested by @lurch.
objexcept: Don't store args tuple within exception object.

To avoid pointer-to-field GC problem.
vm: Add rudimentary bytecode execution tracing capability.