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

fusl/src/math/scalbnl.c

Index: fusl/src/math/scalbnl.c
diff --git a/fusl/src/math/scalbnl.c b/fusl/src/math/scalbnl.c
new file mode 100644
index 0000000000000000000000000000000000000000..08a4c58754d8a237f4441f10b1cce610ef885e43
--- /dev/null
+++ b/fusl/src/math/scalbnl.c
@@ -0,0 +1,36 @@
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double scalbnl(long double x, int n)
+{
+	return scalbn(x, n);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+long double scalbnl(long double x, int n)
+{
+	union ldshape u;
+
+	if (n > 16383) {
+		x *= 0x1p16383L;
+		n -= 16383;
+		if (n > 16383) {
+			x *= 0x1p16383L;
+			n -= 16383;
+			if (n > 16383)
+				n = 16383;
+		}
+	} else if (n < -16382) {
+		x *= 0x1p-16382L;
+		n += 16382;
+		if (n < -16382) {
+			x *= 0x1p-16382L;
+			n += 16382;
+			if (n < -16382)
+				n = -16382;
+		}
+	}
+	u.f = 1.0;
+	u.i.se = 0x3fff + n;
+	return x * u.f;
+}
+#endif