io issues on osx

Using cmake I was able to compile io, simply using:
mkdir build && cd build
cmake ..
make

then I tried to use the static library libiovmall_static.a inside my Cocoa app but as soon as I add the header:
#import "IoState.h"

I receive one linker error and two warning:
ld: duplicate symbol _CollectorMarker_clear in /Users/marco/Desktop/Merlin/io/libiovmall_static.a(CollectorMarker.c.o) and /Users/marco/Desktop/Merlin/build/Merlin.build/Debug/Merlin.build/Objects-normal/x86_64/MerlinAppDelegate.o

and the warnings are about nil and _POSIX2_UPE redefined.

I am an io newbie but not a developer newbie and I really find difficult to move one with all these issues and especially with the complete lack of documentation about how to embed io and how to use it inside a C app.

Again, any help is really appreciated.
Thanks.
--
Marco Bambini
[email protected]