Hello,

The function:

	get_frame_pc(fi)
		=== fi->pc

is about to be changed to:

	get_frame_pc(fi)
		=== fi->next->prev_pc.value;

but that doesn't work very well when fi->next isn't initialized.

The attached modifies legacy_get_prev_frame() so that it initializes 
prev->next var earlier in the frame's creation and thus ensuring that 
get_frame_pc() can still work.

The new frame code doesn't suffer from this problem.

committed,
Andrew