According to users on #charybdis, everything is fine with Xcode 4 and OS X 10.8.
Trying to build on 10.9 however fails with the following error:
build ==> modules
gcc -fPIC -DPIC -shared -I../include -I../libratbox/include -O0 -Wall -std=gnu99 -g -g -O2 -DIRCD_PREFIX=\"/Users/clint/ircd\" core/m_ban.c -o core/m_ban.so
Undefined symbols for architecture x86_64:
"_CAP_BAN", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_CAP_TS6", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_ConfigFileEntry", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_add_conf_by_address", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_add_to_resv_hash", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_check_klines", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_check_klines_event", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_check_xlines", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_deactivate_conf", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_find_prop_ban", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_get_oper_name", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_ilog", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_kline_queued", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_m_ignore", referenced from:
_ban_msgtab in m_ban-zwerhZ.o
"_m_unregistered", referenced from:
_ban_msgtab in m_ban-zwerhZ.o
"_make_conf", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_operhash_add", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_operhash_delete", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_prop_bans", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_rb_current_time", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_rb_event_addonce", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_rb_make_rb_dlink_node", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_rb_outofmemory", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_rb_strlcpy", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_remove_reject_mask", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_resv_chan_forcepart", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_resv_conf_list", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_sendto_one_notice", referenced from:
_m_ban in m_ban-zwerhZ.o
_ms_ban in m_ban-zwerhZ.o
"_sendto_realops_snomask", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_sendto_server", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_valid_wild_card", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_valid_wild_card_simple", referenced from:
_ms_ban in m_ban-zwerhZ.o
"_xline_conf_list", referenced from:
_ms_ban in m_ban-zwerhZ.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [core/m_ban.so] Error 1
make: *** [build] Error 2