Variant of patch #697613: don't exit the interpreter on a SystemExit
exception if the -i command line option or PYTHONINSPECT environment
variable is given, but break into the interactive interpreter just like
on other exceptions or normal program exit.
 (backport)
diff --git a/Modules/main.c b/Modules/main.c
index 7594a76..2dbdfe9 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -216,13 +216,11 @@
 	char *module = NULL;
 	FILE *fp = stdin;
 	char *p;
-	int inspect = 0;
 	int unbuffered = 0;
 	int skipfirstline = 0;
 	int stdin_is_interactive = 0;
 	int help = 0;
 	int version = 0;
-	int saw_inspect_flag = 0;
 	int saw_unbuffered_flag = 0;
 	PyCompilerFlags cf;
 
@@ -297,8 +295,7 @@
 			/* NOTREACHED */
 
 		case 'i':
-			inspect++;
-			saw_inspect_flag = 1;
+			Py_InspectFlag++;
 			Py_InteractiveFlag++;
 			break;
 
@@ -369,9 +366,9 @@
 		return 0;
 	}
 
-	if (!saw_inspect_flag &&
+	if (!Py_InspectFlag &&
 	    (p = Py_GETENV("PYTHONINSPECT")) && *p != '\0')
-		inspect = 1;
+		Py_InspectFlag = 1;
 	if (!saw_unbuffered_flag &&
 	    (p = Py_GETENV("PYTHONUNBUFFERED")) && *p != '\0')
 		unbuffered = 1;
@@ -499,7 +496,7 @@
 
 	PySys_SetArgv(argc-_PyOS_optind, argv+_PyOS_optind);
 
-	if ((inspect || (command == NULL && filename == NULL && module == NULL)) &&
+	if ((Py_InspectFlag || (command == NULL && filename == NULL && module == NULL)) &&
 	    isatty(fileno(stdin))) {
 		PyObject *v;
 		v = PyImport_ImportModule("readline");
@@ -518,6 +515,7 @@
 	}
 	else {
 		if (filename == NULL && stdin_is_interactive) {
+			Py_InspectFlag = 0; /* do exit on SystemExit */
 			RunStartupFile(&cf);
 		}
 		/* XXX */
@@ -530,16 +528,18 @@
 	/* Check this environment variable at the end, to give programs the
 	 * opportunity to set it from Python.
 	 */
-	if (!saw_inspect_flag &&
+	if (!Py_InspectFlag &&
 	    (p = Py_GETENV("PYTHONINSPECT")) && *p != '\0')
 	{
-		inspect = 1;
+		Py_InspectFlag = 1;
 	}
 
-	if (inspect && stdin_is_interactive &&
-	    (filename != NULL || command != NULL || module != NULL))
+	if (Py_InspectFlag && stdin_is_interactive &&
+	    (filename != NULL || command != NULL || module != NULL)) {
+		Py_InspectFlag = 0;
 		/* XXX */
 		sts = PyRun_AnyFileFlags(stdin, "<stdin>", &cf) != 0;
+	}
 
 	WaitForThreadShutdown();