* pythonmain.c: -k option, usage message, more environment flags.
  (the latter also in frozenmain.c)
* ceval.c: global 'killprint' flag raises exception when printing an
  expression statement's value (useful for finding stray output)
* timemodule.c: add asctime() and ctime().  Change julian date to
  1-based origin (as intended and documented).
* Removed unused DO_TIMES stuff from timemodule.c.  Added 'epoch' and
  'day0' globals (year where time.time() == 0 and day of the week the
  epoch started).
diff --git a/Python/ceval.c b/Python/ceval.c
index 1c12d9c..8ed4663 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -49,6 +49,9 @@
 #define CHECKEXC 1	/* Double-check exception checking */
 #endif
 
+/* Global option, may be set by main() */
+int killprint;
+
 
 /* Forward declarations */
 
@@ -639,6 +642,11 @@
 				softspace(x, 1);
 				err = writeobject(v, x, 0);
 				flushline();
+				if (killprint) {
+					err_setstr(RuntimeError,
+					      "printing expression statement");
+					x = 0;
+				}
 			}
 			DECREF(v);
 			break;