mesa compile fixes for Clang / VS2013

src/mesa/main/imports.h

 /*
  * Mesa 3-D graphics library
  * Version:  7.5
  *
  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
@@ skipping 127 matching lines @@
 #define sinhf(f) ((float) sinh(f))
 #define sqrtf(f) ((float) sqrt(f))
 #define tanf(f) ((float) tan(f))
 #define tanhf(f) ((float) tanh(f))
 #define acoshf(f) ((float) acosh(f))
 #define asinhf(f) ((float) asinh(f))
 #define atanhf(f) ((float) atanh(f))
 #endif
 
 #if defined(_MSC_VER)
+#if _MSC_VER < 1800  /* Not required on VS2013 and above. */
 static inline float truncf(float x) { return x < 0.0f ? ceilf(x) : floorf(x); }
 static inline float exp2f(float x) { return powf(2.0f, x); }
 static inline float log2f(float x) { return logf(x) * 1.442695041f; }
 static inline float asinhf(float x) { return logf(x + sqrtf(x * x + 1.0f)); }
 static inline float acoshf(float x) { return logf(x + sqrtf(x * x - 1.0f)); }
 static inline float atanhf(float x) { return (logf(1.0f + x) - logf(1.0f - x)) / 2.0f; }
 static inline int isblank(int ch) { return ch == ' ' || ch == '\t'; }
 #define strtoll(p, e, b) _strtoi64(p, e, b)
+#endif  /* _MSC_VER < 1800 */
 #endif
 /*@}*/
 
 /***
  *** LOG2: Log base 2 of float
  ***/
 #ifdef USE_IEEE
 #if 0
 /* This is pretty fast, but not accurate enough (only 2 fractional bits).
  * Based on code from http://www.stereopsis.com/log2.html
@@ skipping 478 matching lines @@
 #define snprintf _snprintf
 #endif
 
 
 #ifdef __cplusplus
 }
 #endif
 
 
 #endif /* IMPORTS_H */