Enable crc instructions when building for arm64 cpu (iOS)#1154

jnavarrom wants to merge 1 commit intoweidai11:masterweidai11/cryptopp:masterfrom

jnavarrom:issue#1074-build-for-iphoneos-arm64-with-crcjnavarrom/cryptopp:issue#1074-build-for-iphoneos-arm64-with-crcCopy head branch name to clipboard