rt.dwarfeh: Free current inflight exception before calling _d_print_throwable()

As _d_print_throwable() itself may throw multiple times when calling
core.demangle, and with the uncaught exception still on the EH stack,
this doesn't bode well with core.demangle's error recovery.

Author: ibuclaw

src/rt/dwarfeh.d

@@ -229,6 +229,11 @@ extern(C) void _d_throwdwarf(Throwable o)
              * try/catch.
              */
             fprintf(stderr, "uncaught exception\n");
+            /**
+            As _d_print_throwable() itself may throw multiple times when calling core.demangle,
+            and with the uncaught exception still on the EH stack, this doesn't bode well with core.demangle's error recovery.
+            */
+            __dmd_begin_catch(&eh.exception_object);
             _d_print_throwable(o);
             abort();
             assert(0);

test/exceptions/Makefile

@@ -46,11 +46,14 @@ $(ROOT)/unknown_gc.done: STDERR_EXP="'unknowngc'"
 $(ROOT)/static_dtor.done: STDERR_EXP="dtor_called_more_than_once"
 $(ROOT)/future_message.done: STDERR_EXP="exception I have a custom message. exception exception "
 $(ROOT)/static_dtor.done: NEGATE=!
-$(ROOT)/rt_trap_exceptions.done: STDERR_EXP="uncaught exception\nobject.Exception@rt_trap_exceptions.d(11): exception"
-$(ROOT)/rt_trap_exceptions.done: NEGATE=!
+$(ROOT)/rt_trap_exceptions.done: STDERR_EXP="object.Exception@src/rt_trap_exceptions.d(12): this will abort"
+$(ROOT)/rt_trap_exceptions.done: STDERR_EXP2="src/rt_trap_exceptions.d:8 main"
 $(ROOT)/%.done: $(ROOT)/%
 	@echo Testing $*
 	$(NEGATE) $(QUIET)$(TIMELIMIT)$(ROOT)/$* $(RUN_ARGS) 2>&1 1>/dev/null | grep -qF $(STDERR_EXP)
+	if [ ! -z "$(STDERR_EXP2)" ] ; then \
+		$(NEGATE) $(QUIET)$(TIMELIMIT)$(ROOT)/$* $(RUN_ARGS) 2>&1 1>/dev/null | grep -qF $(STDERR_EXP2); \
+	fi
 	@touch $@
 
 $(ROOT)/unittest_assert: DFLAGS+=-unittest