Add a "fork" of musl as //fusl.

fusl/src/math/scalb.c

+/* origin: FreeBSD /usr/src/lib/msun/src/e_scalb.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+/*
+ * scalb(x, fn) is provide for
+ * passing various standard test suite. One
+ * should use scalbn() instead.
+ */
+
+#define _GNU_SOURCE
+#include <math.h>
+
+double scalb(double x, double fn)
+{
+        if (isnan(x) || isnan(fn))
+                return x*fn;
+        if (!isfinite(fn)) {
+                if (fn > 0.0)
+                        return x*fn;
+                else
+                        return x/(-fn);
+        }
+        if (rint(fn) != fn) return (fn-fn)/(fn-fn);
+        if ( fn > 65000.0) return scalbn(x, 65000);
+        if (-fn > 65000.0) return scalbn(x,-65000);
+        return scalbn(x,(int)fn);
+}