use const for readonly strings and set some functions to static

source/blender/python/generic/bpy_internal_import.c

@@ -124,7 +124,7 @@ PyObject *bpy_text_import(Text *text)
 	return PyImport_ExecCodeModule(modulename, text->compiled);
 }
 
-PyObject *bpy_text_import_name(char *name, int *found)
+PyObject *bpy_text_import_name(const char *name, int *found)
 {
 	Text *text;
 	char txtname[MAX_ID_NAME-2];