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

fusl/src/math/exp10l.c

+#define _GNU_SOURCE
+#include <float.h>
+#include <math.h>
+#include "libc.h"
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double exp10l(long double x)
+{
+        return exp10(x);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+long double exp10l(long double x)
+{
+        static const long double p10[] = {
+                1e-15L, 1e-14L, 1e-13L, 1e-12L, 1e-11L, 1e-10L,
+                1e-9L, 1e-8L, 1e-7L, 1e-6L, 1e-5L, 1e-4L, 1e-3L, 1e-2L, 1e-1L,
+                1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
+                1e10, 1e11, 1e12, 1e13, 1e14, 1e15
+        };
+        long double n, y = modfl(x, &n);
+        union ldshape u = {n};
+        /* fabsl(n) < 16 without raising invalid on nan */
+        if ((u.i.se & 0x7fff) < 0x3fff+4) {
+                if (!y) return p10[(int)n+15];
+                y = exp2l(3.32192809488736234787031942948939L * y);
+                return y * p10[(int)n+15];
+        }
+        return powl(10.0, x);
+}
+#endif
+
+weak_alias(exp10l, pow10l);