Checking for manifest in comctl32 for custom draw

[Gabriel Ivăncescu]

Trying to implement custom draw for buttons to fix 
https://bugs.winehq.org/show_bug.cgi?id=10531  and I have a question 
about the manifest as mentioned in the bug report.

I notice that the tests already assume that comctl32 has these enabled, 
and they work on Windows, so is it really necessary to check for the 
manifest at all? Obviously, fixing this would only go into 
comctl32/button and not in user32/button because the latter doesn't have 
custom draw on Windows.

Do I still have to check for the manifest? And if so, can someone please 
point me to the right direction on how to do that? I've no knowledge of 
this at all.

Thank you.