Translate E_INDENT to the clearest error message I can think of.
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 87b691a..16aba5c 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -997,6 +997,9 @@
 	case E_EOF:
 		msg = "unexpected EOF while parsing";
 		break;
+	case E_INDENT:
+		msg = "inconsistent use of tabs and spaces in indentation";
+		break;
 	default:
 		fprintf(stderr, "error=%d\n", err->error);
 		msg = "unknown parsing error";