Drop return_addr from struct process

- The only interesting use seems to be in output.c, but there we assume
  we are working with top-of-callstack anyway, and store fetch context
  there, so we can simply fetch the return address this way as well.
diff --git a/handle_event.c b/handle_event.c
index 3101847..8292e5a 100644
--- a/handle_event.c
+++ b/handle_event.c
@@ -622,7 +622,6 @@
 					calc_time_spent(event->proc);
 				}
 			}
-			event->proc->return_addr = brk_addr;
 
 			struct library_symbol *libsym =
 			    event->proc->callstack[i].c_un.libfunc;
@@ -678,8 +677,6 @@
 		if (event->proc->state != STATE_IGNORED
 		    && sbp->libsym != NULL) {
 			event->proc->stack_pointer = get_stack_pointer(event->proc);
-			event->proc->return_addr =
-				get_return_addr(event->proc, event->proc->stack_pointer);
 			callstack_push_symfunc(event->proc, sbp->libsym);
 			output_left(LT_TOF_FUNCTION, event->proc, sbp->libsym);
 		}
diff --git a/output.c b/output.c
index 0005242..57fc7d0 100644
--- a/output.c
+++ b/output.c
@@ -121,12 +121,15 @@
 		}
 	}
 	if (opt_i) {
-		if (is_func)
+		if (is_func) {
+			struct callstack_element *stel
+				= &proc->callstack[proc->callstack_depth - 1];
 			current_column += fprintf(options.output, "[%p] ",
-						  proc->return_addr);
-		else
+						  stel->return_addr);
+		} else {
 			current_column += fprintf(options.output, "[%p] ",
 						  proc->instruction_pointer);
+		}
 	}
 	if (options.indent > 0 && indent) {
 		output_indent(proc);
diff --git a/proc.h b/proc.h
index 1b5fe03..e46b235 100644
--- a/proc.h
+++ b/proc.h
@@ -65,7 +65,7 @@
 		struct library_symbol * libfunc;
 	} c_un;
 	int is_syscall;
-	void * return_addr;
+	arch_addr_t return_addr;
 	struct timeval time_spent;
 	struct fetch_context *fetch_context;
 	struct value_dict *arguments;
@@ -104,7 +104,6 @@
 	/* Arch-dependent: */
 	void * instruction_pointer;
 	void * stack_pointer;      /* To get return addr, args... */
-	void * return_addr;
 	void * arch_ptr;
 
 	/* XXX We would like to replace this with a pointer to ABI