header ppc/types.h collides with a system header of the same name
When building dav1d on an older Darwin PPC system using gcc7, there are build errors that arise because the build accesses "ppc/types.h" in the source tree instead of <ppc/types.h> in the system headers.
One solution would be to rename your header "ppc/types.h" to "ppc/dav1d_types.h" or similar. That is what we did, and it appears to work.