[tproxy] httpd-2.2.14-tproxy compile error on freebsd

Hello all when we patch httpd.tproxy to httpd-2.2.14, and compile it, it returns some error such as prctl(), capset() undefined reference in freebsd. os/unix/.libs/libos.a(unixd.o): In function `keep_capabilities': /root/httpd-2.2.14/os/unix/unixd.c:82: undefined reference to `prctl' os/unix/.libs/libos.a(unixd.o): In function `set_capabilities': /root/httpd-2.2.14/os/unix/unixd.c:99: undefined reference to `capset' *** Error code 1 Stop in /root/httpd-2.2.14. these two functions are linux syscall that only implements on linux! are any freebsd based of these functions? how we can compile it without any error? -- Best regards Dariush Zahedmanesh