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

fusl/include/math.h

+#ifndef _MATH_H
+#define _MATH_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <features.h>
+
+#define __NEED_float_t
+#define __NEED_double_t
+#include <bits/alltypes.h>
+
+#if 100*__GNUC__+__GNUC_MINOR__ >= 303
+#define NAN       __builtin_nanf("")
+#define INFINITY  __builtin_inff()
+#else
+#define NAN       (0.0f/0.0f)
+#define INFINITY  1e5000f
+#endif
+
+#define HUGE_VALF INFINITY
+#define HUGE_VAL  ((double)INFINITY)
+#define HUGE_VALL ((long double)INFINITY)
+
+#define MATH_ERRNO  1
+#define MATH_ERREXCEPT 2
+#define math_errhandling 2
+
+#define FP_ILOGBNAN (-1-(int)(((unsigned)-1)>>1))
+#define FP_ILOGB0 FP_ILOGBNAN
+
+#define FP_NAN       0
+#define FP_INFINITE  1
+#define FP_ZERO      2
+#define FP_SUBNORMAL 3
+#define FP_NORMAL    4
+
+int __fpclassify(double);
+int __fpclassifyf(float);
+int __fpclassifyl(long double);
+
+static __inline unsigned __FLOAT_BITS(float __f)
+{
+        union {float __f; unsigned __i;} __u;
+        __u.__f = __f;
+        return __u.__i;
+}
+static __inline unsigned long long __DOUBLE_BITS(double __f)
+{
+        union {double __f; unsigned long long __i;} __u;
+        __u.__f = __f;
+        return __u.__i;
+}
+
+#define fpclassify(x) ( \
+        sizeof(x) == sizeof(float) ? __fpclassifyf(x) : \
+        sizeof(x) == sizeof(double) ? __fpclassify(x) : \
+        __fpclassifyl(x) )
+
+#define isinf(x) ( \
+        sizeof(x) == sizeof(float) ? (__FLOAT_BITS(x) & 0x7fffffff) == 0x7f800000 : \
+        sizeof(x) == sizeof(double) ? (__DOUBLE_BITS(x) & -1ULL>>1) == 0x7ffULL<<52 : \
+        __fpclassifyl(x) == FP_INFINITE)
+
+#define isnan(x) ( \
+        sizeof(x) == sizeof(float) ? (__FLOAT_BITS(x) & 0x7fffffff) > 0x7f800000 : \
+        sizeof(x) == sizeof(double) ? (__DOUBLE_BITS(x) & -1ULL>>1) > 0x7ffULL<<52 : \
+        __fpclassifyl(x) == FP_NAN)
+
+#define isnormal(x) ( \
+        sizeof(x) == sizeof(float) ? ((__FLOAT_BITS(x)+0x00800000) & 0x7fffffff) >= 0x01000000 : \
+        sizeof(x) == sizeof(double) ? ((__DOUBLE_BITS(x)+(1ULL<<52)) & -1ULL>>1) >= 1ULL<<53 : \
+        __fpclassifyl(x) == FP_NORMAL)
+
+#define isfinite(x) ( \
+        sizeof(x) == sizeof(float) ? (__FLOAT_BITS(x) & 0x7fffffff) < 0x7f800000 : \
+        sizeof(x) == sizeof(double) ? (__DOUBLE_BITS(x) & -1ULL>>1) < 0x7ffULL<<52 : \
+        __fpclassifyl(x) > FP_INFINITE)
+
+int __signbit(double);
+int __signbitf(float);
+int __signbitl(long double);
+
+#define signbit(x) ( \
+        sizeof(x) == sizeof(float) ? (int)(__FLOAT_BITS(x)>>31) : \
+        sizeof(x) == sizeof(double) ? (int)(__DOUBLE_BITS(x)>>63) : \
+        __signbitl(x) )
+
+#define isunordered(x,y) (isnan((x)) ? ((void)(y),1) : isnan((y)))
+
+#define __ISREL_DEF(rel, op, type) \
+static __inline int __is##rel(type __x, type __y) \
+{ return !isunordered(__x,__y) && __x op __y; }
+
+__ISREL_DEF(lessf, <, float_t)
+__ISREL_DEF(less, <, double_t)
+__ISREL_DEF(lessl, <, long double)
+__ISREL_DEF(lessequalf, <=, float_t)
+__ISREL_DEF(lessequal, <=, double_t)
+__ISREL_DEF(lessequall, <=, long double)
+__ISREL_DEF(lessgreaterf, !=, float_t)
+__ISREL_DEF(lessgreater, !=, double_t)
+__ISREL_DEF(lessgreaterl, !=, long double)
+__ISREL_DEF(greaterf, >, float_t)
+__ISREL_DEF(greater, >, double_t)
+__ISREL_DEF(greaterl, >, long double)
+__ISREL_DEF(greaterequalf, >=, float_t)
+__ISREL_DEF(greaterequal, >=, double_t)
+__ISREL_DEF(greaterequall, >=, long double)
+
+#define __tg_pred_2(x, y, p) ( \
+        sizeof((x)+(y)) == sizeof(float) ? p##f(x, y) : \
+        sizeof((x)+(y)) == sizeof(double) ? p(x, y) : \
+        p##l(x, y) )
+
+#define isless(x, y)            __tg_pred_2(x, y, __isless)
+#define islessequal(x, y)       __tg_pred_2(x, y, __islessequal)
+#define islessgreater(x, y)     __tg_pred_2(x, y, __islessgreater)
+#define isgreater(x, y)         __tg_pred_2(x, y, __isgreater)
+#define isgreaterequal(x, y)    __tg_pred_2(x, y, __isgreaterequal)
+
+double      acos(double);
+float       acosf(float);
+long double acosl(long double);
+
+double      acosh(double);
+float       acoshf(float);
+long double acoshl(long double);
+
+double      asin(double);
+float       asinf(float);
+long double asinl(long double);
+
+double      asinh(double);
+float       asinhf(float);
+long double asinhl(long double);
+
+double      atan(double);
+float       atanf(float);
+long double atanl(long double);
+
+double      atan2(double, double);
+float       atan2f(float, float);
+long double atan2l(long double, long double);
+
+double      atanh(double);
+float       atanhf(float);
+long double atanhl(long double);
+
+double      cbrt(double);
+float       cbrtf(float);
+long double cbrtl(long double);
+
+double      ceil(double);
+float       ceilf(float);
+long double ceill(long double);
+
+double      copysign(double, double);
+float       copysignf(float, float);
+long double copysignl(long double, long double);
+
+double      cos(double);
+float       cosf(float);
+long double cosl(long double);
+
+double      cosh(double);
+float       coshf(float);
+long double coshl(long double);
+
+double      erf(double);
+float       erff(float);
+long double erfl(long double);
+
+double      erfc(double);
+float       erfcf(float);
+long double erfcl(long double);
+
+double      exp(double);
+float       expf(float);
+long double expl(long double);
+
+double      exp2(double);
+float       exp2f(float);
+long double exp2l(long double);
+
+double      expm1(double);
+float       expm1f(float);
+long double expm1l(long double);
+
+double      fabs(double);
+float       fabsf(float);
+long double fabsl(long double);
+
+double      fdim(double, double);
+float       fdimf(float, float);
+long double fdiml(long double, long double);
+
+double      floor(double);
+float       floorf(float);
+long double floorl(long double);
+
+double      fma(double, double, double);
+float       fmaf(float, float, float);
+long double fmal(long double, long double, long double);
+
+double      fmax(double, double);
+float       fmaxf(float, float);
+long double fmaxl(long double, long double);
+
+double      fmin(double, double);
+float       fminf(float, float);
+long double fminl(long double, long double);
+
+double      fmod(double, double);
+float       fmodf(float, float);
+long double fmodl(long double, long double);
+
+double      frexp(double, int *);
+float       frexpf(float, int *);
+long double frexpl(long double, int *);
+
+double      hypot(double, double);
+float       hypotf(float, float);
+long double hypotl(long double, long double);
+
+int         ilogb(double);
+int         ilogbf(float);
+int         ilogbl(long double);
+
+double      ldexp(double, int);
+float       ldexpf(float, int);
+long double ldexpl(long double, int);
+
+double      lgamma(double);
+float       lgammaf(float);
+long double lgammal(long double);
+
+long long   llrint(double);
+long long   llrintf(float);
+long long   llrintl(long double);
+
+long long   llround(double);
+long long   llroundf(float);
+long long   llroundl(long double);
+
+double      log(double);
+float       logf(float);
+long double logl(long double);
+
+double      log10(double);
+float       log10f(float);
+long double log10l(long double);
+
+double      log1p(double);
+float       log1pf(float);
+long double log1pl(long double);
+
+double      log2(double);
+float       log2f(float);
+long double log2l(long double);
+
+double      logb(double);
+float       logbf(float);
+long double logbl(long double);
+
+long        lrint(double);
+long        lrintf(float);
+long        lrintl(long double);
+
+long        lround(double);
+long        lroundf(float);
+long        lroundl(long double);
+
+double      modf(double, double *);
+float       modff(float, float *);
+long double modfl(long double, long double *);
+
+double      nan(const char *);
+float       nanf(const char *);
+long double nanl(const char *);
+
+double      nearbyint(double);
+float       nearbyintf(float);
+long double nearbyintl(long double);
+
+double      nextafter(double, double);
+float       nextafterf(float, float);
+long double nextafterl(long double, long double);
+
+double      nexttoward(double, long double);
+float       nexttowardf(float, long double);
+long double nexttowardl(long double, long double);
+
+double      pow(double, double);
+float       powf(float, float);
+long double powl(long double, long double);
+
+double      remainder(double, double);
+float       remainderf(float, float);
+long double remainderl(long double, long double);
+
+double      remquo(double, double, int *);
+float       remquof(float, float, int *);
+long double remquol(long double, long double, int *);
+
+double      rint(double);
+float       rintf(float);
+long double rintl(long double);
+
+double      round(double);
+float       roundf(float);
+long double roundl(long double);
+
+double      scalbln(double, long);
+float       scalblnf(float, long);
+long double scalblnl(long double, long);
+
+double      scalbn(double, int);
+float       scalbnf(float, int);
+long double scalbnl(long double, int);
+
+double      sin(double);
+float       sinf(float);
+long double sinl(long double);
+
+double      sinh(double);
+float       sinhf(float);
+long double sinhl(long double);
+
+double      sqrt(double);
+float       sqrtf(float);
+long double sqrtl(long double);
+
+double      tan(double);
+float       tanf(float);
+long double tanl(long double);
+
+double      tanh(double);
+float       tanhf(float);
+long double tanhl(long double);
+
+double      tgamma(double);
+float       tgammaf(float);
+long double tgammal(long double);
+
+double      trunc(double);
+float       truncf(float);
+long double truncl(long double);
+
+
+#if defined(_XOPEN_SOURCE) || defined(_BSD_SOURCE)
+#undef  MAXFLOAT
+#define MAXFLOAT        3.40282346638528859812e+38F
+#endif
+
+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define M_E             2.7182818284590452354   /* e */
+#define M_LOG2E         1.4426950408889634074   /* log_2 e */
+#define M_LOG10E        0.43429448190325182765  /* log_10 e */
+#define M_LN2           0.69314718055994530942  /* log_e 2 */
+#define M_LN10          2.30258509299404568402  /* log_e 10 */
+#define M_PI            3.14159265358979323846  /* pi */
+#define M_PI_2          1.57079632679489661923  /* pi/2 */
+#define M_PI_4          0.78539816339744830962  /* pi/4 */
+#define M_1_PI          0.31830988618379067154  /* 1/pi */
+#define M_2_PI          0.63661977236758134308  /* 2/pi */
+#define M_2_SQRTPI      1.12837916709551257390  /* 2/sqrt(pi) */
+#define M_SQRT2         1.41421356237309504880  /* sqrt(2) */
+#define M_SQRT1_2       0.70710678118654752440  /* 1/sqrt(2) */
+
+extern int signgam;
+
+double      j0(double);
+double      j1(double);
+double      jn(int, double);
+
+double      y0(double);
+double      y1(double);
+double      yn(int, double);
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define HUGE            3.40282346638528859812e+38F
+
+double      drem(double, double);
+float       dremf(float, float);
+
+int         finite(double);
+int         finitef(float);
+
+double      scalb(double, double);
+float       scalbf(float, float);
+
+double      significand(double);
+float       significandf(float);
+
+double      lgamma_r(double, int*);
+float       lgammaf_r(float, int*);
+
+float       j0f(float);
+float       j1f(float);
+float       jnf(int, float);
+
+float       y0f(float);
+float       y1f(float);
+float       ynf(int, float);
+#endif
+
+#ifdef _GNU_SOURCE
+long double lgammal_r(long double, int*);
+
+void        sincos(double, double*, double*);
+void        sincosf(float, float*, float*);
+void        sincosl(long double, long double*, long double*);
+
+double      exp10(double);
+float       exp10f(float);
+long double exp10l(long double);
+
+double      pow10(double);
+float       pow10f(float);
+long double pow10l(long double);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif