this version of tremor requires a nil check on close_func
https://svn.xiph.org/trunk/Tremor/vorbisfile.c
//
// Prefix header for all source files of the 'CocoaTouchStaticLibrary' target in the 'CocoaTouchStaticLibrary' project.
//
#ifdef __OBJC__
#import <Foundation/Foundation.h>
#endif