The latest slirp commits in QEMU git master (commits 953e7f54e679cd40fff28e29189ed9e24bfb0758, e3078bf40a33b59fa11d077b1d0bb8796470982e, f37343197708d90f119007ce5ecc2503be9c04c1, a68adc220603baffc355ecea8865b3ea9707ab00) fixed this issue.
The latest slirp commits in QEMU git master (commits 953e7f54e679cd4 0fff28e29189ed9 e24bfb0758, e3078bf40a33b59 fa11d077b1d0bb8 796470982e, f37343197708d90 f119007ce5ecc25 03be9c04c1, a68adc220603baf fc355ecea8865b3 ea9707ab00) fixed this issue.