If you have levelDB issue (libleveldb.a / libmemenv.a), plz follow below instruction.
cd %coin_folder%/src/leveldb
TARGET_OS=NATIVE_WINDOWS make libleveldb.a libmemenv.a CC=/mnt/mxe/usr/bin/i686-w64-mingw32.static-gcc CXX=/mnt/mxe/usr/bin/i686-w64-mingw32.static-g++