net/ipsumdump: Unbreak amd64 build after 64825b9

aggwtree.cc:859:7: error: use of undeclared identifier 'bswap_32'

add(bswap_32(ubuf[2*i]), bswap_32(ubuf[2*i + 1]));
    ^

aggwtree.cc:859:28: error: use of undeclared identifier 'bswap_32'

add(bswap_32(ubuf[2*i]), bswap_32(ubuf[2*i + 1]));
                         ^

2 errors generated.
gmake[1]: * [Makefile:46: aggwtree.o] Error 1
gmake[1]: * Waiting for unfinished jobs....
aggtree.cc:1139:7: error: use of undeclared identifier 'bswap_32'

add(bswap_32(ubuf[2*i]), bswap_32(ubuf[2*i + 1]));
    ^

aggtree.cc:1139:28: error: use of undeclared identifier 'bswap_32'

add(bswap_32(ubuf[2*i]), bswap_32(ubuf[2*i + 1]));
                         ^

2 errors generated.