VLC fails to build

[listmember at rinnberger.de]

Hello all,

VLC 2.2.2 fails to build on 10.6.8

the build log gives me in $BUILDDIR/work/vlc-2.2.2/modules/gui/macosx

>> :info:build intf.m:688:91: error: use of undeclared identifier 'DISPATCH_QUEUE_SERIAL'
>> :info:build     informInputChangedQueue = dispatch_queue_create("org.videolan.vlc.inputChangedQueue", DISPATCH_QUEUE_SERIAL);

A search for 'DISPATCH_QUEUE_SERIAL' brought me to

<http://stackoverflow.com/questions/10075083/restkit-undeclared-identifier-dispatch-queue-serial-inside-rkobjectmanager>

which offered a potential solution. 

I am not experienced with the phases in macports build process, so here is my question:

How to pass NULL for the second parameter to dispatch_queue_create() ?

P.S.

the config log gives an error, too:
> conftest.c:11:10: fatal error: 'ac_nonexistent.h' file not found
> #include <ac_nonexistent.h>
>          ^

is this somehow related?

thanks in advance