vm: remove signal_from_leaf flag

Now that the resuming from the signal handler works within leaf procedures, the flag is no longer necessary.

vm/callstack.cpp

@@ -89,15 +89,12 @@ void factor_vm::dispatch_signal_handler(cell *sp, cell *pc, cell handler)
 		of assuming the stack pointer is the right place to put the resume address. */
 		if (offset == 0)
 		{
-			signal_from_leaf = false; // XXX remove this once we're sure leaf works
 			cell newsp = *sp - sizeof(cell);
 			*sp = newsp;
 			*(cell*)newsp = *pc;
 		}
 		else if (offset == 16 - sizeof(cell))
 		{
-			signal_from_leaf = true; // XXX remove this once we're sure leaf works
-
 			// Make a fake frame for the leaf procedure
 			cell leaf_word = find_entry_point_for_address(this, *pc);
 

vm/errors.cpp

@@ -185,9 +185,6 @@ void factor_vm::enqueue_safepoint_sample()
 
 void factor_vm::handle_safepoint()
 {
-	if (signal_from_leaf)
-		std::cout << "XXX SIGNALED FROM LEAF\n";
-
 	code->unguard_safepoint();
 	if (safepoint_fep) {
 		std::cout << "Interrupted\n";

vm/vm.hpp

@@ -68,7 +68,6 @@ struct factor_vm
 	/* Global variables used to pass fault handler state from signal handler
 	to VM */
 	bool signal_resumable;
-	bool signal_from_leaf; // XXX remove this once we're sure leaf works
 	cell signal_number;
 	cell signal_fault_addr;
 	unsigned int signal_fpu_status;