GCC 14 on aarch64 rejects the C code written by GHC with this kind of
error:

   error: assignment to ‘ffi_arg’ {aka ‘long unsigned int’} from ‘HsPtr’ {aka ‘void *’} makes integer from pointer without a cast [-Wint-conversion]
         68 | *(ffi_arg*)resp = cret;
            |                 ^

Add the correct cast.

For more information on this see:
https://fedoraproject.org/wiki/Changes/PortingToModernC



Tested-by: Richard W.M. Jones <rjones@redhat.com>