* io.c (seek_before_access): fixed argument type.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27569 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

io.c

@@ -7911,8 +7911,9 @@ struct seek_arg {
 };
 
 static VALUE
-seek_before_access(struct seek_arg *arg)
+seek_before_access(VALUE argp)
 {
+    struct seek_arg *arg = (struct seek_arg *)argp;
     rb_io_binmode(arg->io);
     return rb_io_seek(arg->io, arg->offset, arg->mode);
 }
@@ -7964,7 +7965,7 @@ rb_io_s_read(int argc, VALUE *argv, VALUE io)
 	sarg.io = arg.io;
 	sarg.offset = offset;
 	sarg.mode = SEEK_SET;
-	rb_protect((VALUE (*)(VALUE))seek_before_access, (VALUE)&sarg, &state);
+	rb_protect(seek_before_access, (VALUE)&sarg, &state);
 	if (state) {
 	    rb_io_close(arg.io);
 	    rb_jump_tag(state);