v0.5.0 fails to build on 32-bit architectures due to -Werror
Regressed by !64 (merged). Affects armv7, i386, powerpc.
layer.c:76:41: error: implicit conversion changes signedness: 'ssize_t' (aka 'int') to 'enum liftoff_core_property' [-Werror,-Wsign-conversion]
return layer_get_core_property(layer, core_prop_idx);
~~~~~~~~~~~~~~~~~~~~~~~ ^~~~~~~~~~~~~