util: Add _BitScanForward intrinsic's declaration.

It is missing in some Microsoft DDKs.

diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index b12c97d..b428dc5 100644 (file)
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -354,7 +354,9 @@ util_is_pot(unsigned x)
  * Find first bit set in word.  Least significant bit is 1.
  * Return 0 if no bits set.
  */
-#if defined(_MSC_VER) && _MSC_VER >= 1300
+#if defined(_MSC_VER) && _MSC_VER >= 1300 && (_M_IX86 || _M_AMD64 || _M_IA64)
+unsigned char _BitScanForward(unsigned long* Index, unsigned long Mask);
+#pragma intrinsic(_BitScanForward)
 static INLINE
 unsigned long ffs( unsigned long u )
 {