add numerical recipes library

lib/nr/ansi/recipes/wt1.c

@@ -0,0 +1,13 @@
+
+void wt1(float a[], unsigned long n, int isign,
+	void (*wtstep)(float [], unsigned long, int))
+{
+	unsigned long nn;
+
+	if (n < 4) return;
+	if (isign >= 0) {
+		for (nn=n;nn>=4;nn>>=1) (*wtstep)(a,nn,isign);
+	} else {
+		for (nn=4;nn<=n;nn<<=1) (*wtstep)(a,nn,isign);
+	}
+}