1) At the beginning of makefiles (for netcoind .exe) add if necessary:
# Copyright (c) 2009-2010 Satoshi Nakamoto
# Distributed under the MIT/X11 software license, see the accompanying
# file license.txt or http://www.opensource.org/licenses/mit-license.php.
CXX ?= g++
USE_UPNP:=0
2) then change every appearance of g++ with $(CXX)
3) Below obj/noui.o add:
obj/noui.o \
obj/zerocoin/Accumulator.o \
obj/zerocoin/AccumulatorProofOfKnowledge.o \
obj/zerocoin/Coin.o \
obj/zerocoin/CoinSpend.o \
obj/zerocoin/Commitment.o \
obj/zerocoin/ParamGeneration.o \
obj/zerocoin/Params.o \
obj/zerocoin/SerialNumberSignatureOfKnowledge.o \
obj/zerocoin/SpendMetaData.o \
obj/zerocoin/ZeroTest.o
4) In makefiles (i am interested in makefile.mingw ) below obj/%.o: .... add commands for compiling obj/zerocoin/%.o : ...
obj/%.o: %.cpp $(HEADERS)
$(CXX) -c $(CFLAGS) -o $@ $<
obj/zerocoin/%.o: zerocoin/%.cpp
$(CXX) -c $(CFLAGS) -o $@ $<