Is there a reason that the following constants in "fpcsrc/packages/rtl-extra/src/unix/ipc.pp" are not included for Darwin? The same definitions are defined in Yosemite at /usr/include/sys/sem.h. Both SEM_GETVAL and SEM_SETVAL are used by ibx.
{$if not defined(aix) and not defined(darwin)}
SEM_GETNCNT = 3; { Return the value of sempid (READ) }
SEM_GETPID = 4; { Return the value of semval (READ) }
SEM_GETVAL = 5; { Return semvals into arg.array (READ) }
SEM_GETALL = 6; { Return the value of semzcnt (READ) }
SEM_GETZCNT = 7; { Set the value of semval to arg.val (ALTER) }
SEM_SETVAL = 8; { Set semvals from arg.array (ALTER) }
SEM_SETALL = 9;
{$endif}