[mythtv] Compile error "invalid cast"

[David Hampton]

On Thu, 2018-10-04 at 13:01 -0400, Peter Bennett wrote:
> Hi David
> 
> I am getting this error compiling master on raspberry pi. Do you
> know 
> what caused it? My response would be to change it to the simple cast 
> (unsigned char*) (h), but maybe there is a better way, or maybe that 
> will not work.
> 
> videoout_omx.cpp:62:77: error: invalid cast from type
> ‘std::nullptr_t’ 
> to type ‘unsigned char*’
>   #define FRAMESETHDR(f,h) ((f)->priv[3] = reinterpret_cast<unsigned 
> char* >(h))
> ^
> videoout_omx.cpp:1417:9: note: in expansion of macro ‘FRAMESETHDR’
>           FRAMESETHDR(vf, nullptr);
>           ^

It seems that nullptr and reinterpret_cast don't play well together.
There's even something about it on the cppreference pages.  I'm working
on a fix and should have it committed soon.  The test compiles also
turned up a couple of other instances of '0' that should be nullptr, so
I'm fixing those too.

David