Hello,

This patch cleans up just one tiny part of the new merged 
call_function_by_hand().

It teases out an explicit "bp_addr" variable that contains the address 
of the breakpoint that the called function is to return to.  By doing 
this certain logic (such as the computation of sal.pc used to create the 
breakpoint) is simplified; and other logic (such as the initial 
computation of the "bp_addr") is localized.

The only depressing bit in this cleanup is that it is now pretty clear 
how messed up the logic to compute the ON_STACK breakpoint addr has become.

committed,
Andrew