Missing _BitScanReverse64()

[Gisle Vanem]

I'm on Win-XP (32bit, MSVC v16) and get a link error on a
missing '__BitScanReverse64()' in test-count-leading-zeros.c:.
Here is the dis-asm:

 _count_leading_zeros_ll:
         push            ebp
         mov             ebp,esp
         sub             esp,0x00000008
 X$72:
         mov             eax,dword ptr 0xc[ebp]
         push            eax
         mov             ecx,dword ptr 0x8[ebp]
         push            ecx
         lea             edx,-0x4[ebp]
         push            edx
         call            j^__BitScanReverse64

According to MSVC's <intrin.h>, the intrinsic for this function only
exists on 64-bit machines:

/*__MACHINEW64          : WIN64(tm), 64 bit compilers only */
  __MACHINEW64(unsigned char _BitScanForward64(unsigned long* Index,
               unsigned __int64 Mask))

--
--gv