This is a prerequisite for anything IFUNC in the ELFv2 / clang switch.
Since probing cpu info on powerpc is a privileged operation, define that we pass AT_HWCAP / AT_HWCAP2 through as cpu_features and cpu_features2 to ifunc resolvers. (This is particularly important when dealing with non-PLT GNU IFUNC, which is not allowed to PLT call from resolvers and therefore can't access global variables.)
This naming convention matches how we expose these two variables in machine/cpu.h. It is a FreeBSD/powerpc specific convention.