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

fusl/include/float.h

+#ifndef _FLOAT_H
+#define _FLOAT_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int __flt_rounds(void);
+#define FLT_ROUNDS (__flt_rounds())
+
+#define FLT_RADIX 2
+
+#define FLT_TRUE_MIN 1.40129846432481707092e-45F
+#define FLT_MIN 1.17549435082228750797e-38F
+#define FLT_MAX 3.40282346638528859812e+38F
+#define FLT_EPSILON 1.1920928955078125e-07F
+
+#define FLT_MANT_DIG 24
+#define FLT_MIN_EXP (-125)
+#define FLT_MAX_EXP 128
+#define FLT_HAS_SUBNORM 1
+
+#define FLT_DIG 6
+#define FLT_DECIMAL_DIG 9
+#define FLT_MIN_10_EXP (-37)
+#define FLT_MAX_10_EXP 38
+
+#define DBL_TRUE_MIN 4.94065645841246544177e-324
+#define DBL_MIN 2.22507385850720138309e-308
+#define DBL_MAX 1.79769313486231570815e+308
+#define DBL_EPSILON 2.22044604925031308085e-16
+
+#define DBL_MANT_DIG 53
+#define DBL_MIN_EXP (-1021)
+#define DBL_MAX_EXP 1024
+#define DBL_HAS_SUBNORM 1
+
+#define DBL_DIG 15
+#define DBL_DECIMAL_DIG 17
+#define DBL_MIN_10_EXP (-307)
+#define DBL_MAX_10_EXP 308
+
+#define LDBL_HAS_SUBNORM 1
+#define LDBL_DECIMAL_DIG DECIMAL_DIG
+
+#include <bits/float.h>
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif