Indent the #error so that a strict K&R cpp doesn't complain.
diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 92330b4..698b935 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -65,7 +65,7 @@
 #endif
 
 #if TKMAJORMINOR < 4001
-#error "Tk 4.0 or 3.x are not supported -- use 4.1 or higher"
+	#error "Tk 4.0 or 3.x are not supported -- use 4.1 or higher"
 #endif
 
 #if TKMAJORMINOR < 8000 || !defined(MS_WINDOWS) && !defined(macintosh)