add part of opencv

Lib/opencv/sources/cmake/checks/cpu_popcnt.cpp

@@ -0,0 +1,24 @@
+#ifdef _MSC_VER
+#  include <nmmintrin.h>
+#  if defined(_M_X64)
+#    define CV_POPCNT_U64 _mm_popcnt_u64
+#  endif
+#  define CV_POPCNT_U32 _mm_popcnt_u32
+#elif defined(__POPCNT__)
+#  include <popcntintrin.h>
+#  if defined(__x86_64__)
+#    define CV_POPCNT_U64 __builtin_popcountll
+#  endif
+#  define CV_POPCNT_U32 __builtin_popcount
+#else
+#  error "__POPCNT__ is not defined by compiler"
+#endif
+
+int main()
+{
+#ifdef CV_POPCNT_U64
+    int i = CV_POPCNT_U64(1);
+#endif
+    int j = CV_POPCNT_U32(1);
+    return 0;
+}