Fast CRC implementations ported from Intel's efforts

Provides fast CRC32C with PCLMULQDQ instructions in Golang

The white papers on CRC32C calculations with PCLMULQDQ instruction can be
  downloaded from:

http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/crc-iscsi-polynomial-crc32-instruction-paper.pdf
http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-paper.pdf

pkgs/crc32c/cpu/cpu.go

@@ -0,0 +1,18 @@
+// +build linux,amd64
+
+package cpu
+
+// #include "cpu.h"
+import "C"
+
+func HasSSE41() int {
+	return int(C.has_sse41())
+}
+
+func HasAVX() int {
+	return int(C.has_avx())
+}
+
+func HasAVX2() int {
+	return int(C.has_avx2())
+}