[x264-devel] fix for MSVC

[David Lariviere]

To fix building on MSVC, need to
1) add cabac-a.asm to Core\x86 (and set custom build step to match all other
*.a files in same folder group)
2) Add the below to osdep.h
//fixes logf bug in MSVC's math.h
//see
http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?Feedbac
kID=98751
//note this will only work if math.h is included before osdep.h
#ifdef _MSC_VER
#if !defined (_M_IA64) && !defined (_M_AMD64)
#undef logf
#define logf(x)     ((float)log((double)(x)))
#endif    // !defined (_M_IA64) && !defined (_M_AMD64)
#endif 

Tested (and mentioned bug manifested) on MSVC 2003. 

- David Lariviere