Initial QSfera import

Server/vendor/github.com/cloudflare/circl/math/integer.go

@@ -0,0 +1,16 @@
+package math
+
+import "math/bits"
+
+// NextPow2 finds the next power of two (N=2^k, k>=0) greater than n.
+// If n is already a power of two, then this function returns n, and log2(n).
+func NextPow2(n uint) (N uint, k uint) {
+	if bits.OnesCount(n) == 1 {
+		k = uint(bits.TrailingZeros(n))
+		N = n
+	} else {
+		k = uint(bits.Len(n))
+		N = uint(1) << k
+	}
+	return
+}