* io.c (rb_sysopen_internal): removed const qualifier.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24597 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

io.c

@@ -4456,7 +4456,7 @@ sysopen_func(void *ptr)
 }
 
 static inline int
-rb_sysopen_internal(const struct sysopen_struct *data)
+rb_sysopen_internal(struct sysopen_struct *data)
 {
     return (int)rb_thread_blocking_region(sysopen_func, data, RUBY_UBF_IO, 0);
 }