Error out if NDEBUG is defined
Error out if NDEBUG is defined

At some point meson #defined NDEBUG depending on the build type, thus
disabling asserts. libratbag relies on those, so let's error out if NDEBUG is
defined.

Related #685

libratbag/libratbag,whot/libratbag,whot/libratbag,whot/libratbag,libratbag/libratbag,libratbag/libratbag