Allow for multicore compiling on quadcores, everyone has one right? :P It has perfomance benifits on single cores too so it's all good =)
#ifndef _OS_H
#define _OS_H
/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
* *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
* *
********************************************************************
function: #ifdef jail to whip a few platforms into the UNIX ideal.
********************************************************************/
#include <math.h>
#include "os_types.h"
#ifndef _V_IFDEFJAIL_H_
# define _V_IFDEFJAIL_H_
# ifdef __GNUC__
# define STIN static __inline__
# elif _WIN32
# define STIN static __inline
# endif
#else
# define STIN static
#endif
#ifndef M_PI
# define M_PI (3.1415926536f)
#endif
#ifdef _WIN32
# include <malloc.h>
# define rint(x) (floor((x)+0.5f))
# define NO_FLOAT_MATH_LIB
# define FAST_HYPOT(a, b) sqrt((a)*(a) + (b)*(b))
# define LITTLE_ENDIAN 1
# define BYTE_ORDER LITTLE_ENDIAN
#endif
#ifdef HAVE_ALLOCA_H
# include <alloca.h>
#endif
#ifdef USE_MEMORY_H
# include <memory.h>
#endif
#ifndef min
# define min(x,y) ((x)>(y)?(y):(x))
#endif
#ifndef max
# define max(x,y) ((x)<(y)?(y):(x))
#endif
#endif /* _OS_H */