Revert r80580 due to some unintended side effects. See issue #8202 for details.
diff --git a/Modules/main.c b/Modules/main.c
index 7d735a8..a13d166 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -519,10 +519,12 @@
     }
 
     if (module != NULL) {
-        /* Backup _PyOS_optind and force sys.argv[0] = '-m'
-           so that PySys_SetArgv correctly sets sys.path[0] to ''*/
+        /* Backup _PyOS_optind and force sys.argv[0] = '-c'
+           so that PySys_SetArgv correctly sets sys.path[0] to ''
+           rather than looking for a file called "-m". See
+           tracker issue #8202 for details. */
         _PyOS_optind--;
-        argv[_PyOS_optind] = "-m";
+        argv[_PyOS_optind] = "-c";
     }
 
     PySys_SetArgv(argc-_PyOS_optind, argv+_PyOS_optind);