I see you're started with the modification. Just to let you know in advance, I don't use #include "p2pkh_decoder.h" or p2pkh_decoder. Using them costs around 10-15 Mkeys/s in performance. Comparing HASH160 directly is much faster than decoding to a P2PKH address and then comparing. Additionally, it will be even slower if the comparison is based on the decoded address.