vaapi: check for static builds and silence clang warnings
vaapi: libs: Use unsized arrays as parameters.
Instead of defining a sized array for function signature, use it
unsized (a pointer alias, basically). In this way clang warning is
silenced:
warning: ‘fill_profiles’ accessing 64 bytes in a region of size 12 [-Wstringop-overflow=]
vaapi: meson: Fail if static build.
And initialize the plugin array.