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

fusl/include/stdlib.h

+#ifndef _STDLIB_H
+#define _STDLIB_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <features.h>
+
+#ifdef __cplusplus
+#define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
+
+#define __NEED_size_t
+#define __NEED_wchar_t
+
+#include <bits/alltypes.h>
+
+int atoi (const char *);
+long atol (const char *);
+long long atoll (const char *);
+double atof (const char *);
+
+float strtof (const char *__restrict, char **__restrict);
+double strtod (const char *__restrict, char **__restrict);
+long double strtold (const char *__restrict, char **__restrict);
+
+long strtol (const char *__restrict, char **__restrict, int);
+unsigned long strtoul (const char *__restrict, char **__restrict, int);
+long long strtoll (const char *__restrict, char **__restrict, int);
+unsigned long long strtoull (const char *__restrict, char **__restrict, int);
+
+int rand (void);
+void srand (unsigned);
+
+void *malloc (size_t);
+void *calloc (size_t, size_t);
+void *realloc (void *, size_t);
+void free (void *);
+void *aligned_alloc(size_t alignment, size_t size);
+
+_Noreturn void abort (void);
+int atexit (void (*) (void));
+_Noreturn void exit (int);
+_Noreturn void _Exit (int);
+int at_quick_exit (void (*) (void));
+_Noreturn void quick_exit (int);
+
+char *getenv (const char *);
+
+int system (const char *);
+
+void *bsearch (const void *, const void *, size_t, size_t, int (*)(const void *, const void *));
+void qsort (void *, size_t, size_t, int (*)(const void *, const void *));
+
+int abs (int);
+long labs (long);
+long long llabs (long long);
+
+typedef struct { int quot, rem; } div_t;
+typedef struct { long quot, rem; } ldiv_t;
+typedef struct { long long quot, rem; } lldiv_t;
+
+div_t div (int, int);
+ldiv_t ldiv (long, long);
+lldiv_t lldiv (long long, long long);
+
+int mblen (const char *, size_t);
+int mbtowc (wchar_t *__restrict, const char *__restrict, size_t);
+int wctomb (char *, wchar_t);
+size_t mbstowcs (wchar_t *__restrict, const char *__restrict, size_t);
+size_t wcstombs (char *__restrict, const wchar_t *__restrict, size_t);
+
+#define EXIT_FAILURE 1
+#define EXIT_SUCCESS 0
+
+size_t __ctype_get_mb_cur_max(void);
+#define MB_CUR_MAX (__ctype_get_mb_cur_max())
+
+#define RAND_MAX (0x7fffffff)
+
+
+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
+ || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
+ || defined(_BSD_SOURCE)
+
+#define WNOHANG    1
+#define WUNTRACED  2
+
+#define WEXITSTATUS(s) (((s) & 0xff00) >> 8)
+#define WTERMSIG(s) ((s) & 0x7f)
+#define WSTOPSIG(s) WEXITSTATUS(s)
+#define WIFEXITED(s) (!WTERMSIG(s))
+#define WIFSTOPPED(s) ((short)((((s)&0xffff)*0x10001)>>8) > 0x7f00)
+#define WIFSIGNALED(s) (((s)&0xffff)-1U < 0xffu)
+
+int posix_memalign (void **, size_t, size_t);
+int setenv (const char *, const char *, int);
+int unsetenv (const char *);
+int mkstemp (char *);
+int mkostemp (char *, int);
+char *mkdtemp (char *);
+int getsubopt (char **, char *const *, char **);
+int rand_r (unsigned *);
+
+#endif
+
+
+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
+ || defined(_BSD_SOURCE)
+char *realpath (const char *__restrict, char *__restrict);
+long int random (void);
+void srandom (unsigned int);
+char *initstate (unsigned int, char *, size_t);
+char *setstate (char *);
+int putenv (char *);
+int posix_openpt (int);
+int grantpt (int);
+int unlockpt (int);
+char *ptsname (int);
+char *l64a (long);
+long a64l (const char *);
+void setkey (const char *);
+double drand48 (void);
+double erand48 (unsigned short [3]);
+long int lrand48 (void);
+long int nrand48 (unsigned short [3]);
+long mrand48 (void);
+long jrand48 (unsigned short [3]);
+void srand48 (long);
+unsigned short *seed48 (unsigned short [3]);
+void lcong48 (unsigned short [7]);
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#include <alloca.h>
+char *mktemp (char *);
+int mkstemps (char *, int);
+int mkostemps (char *, int, int);
+void *valloc (size_t);
+void *memalign(size_t, size_t);
+int getloadavg(double *, int);
+int clearenv(void);
+#define WCOREDUMP(s) ((s) & 0x80)
+#define WIFCONTINUED(s) ((s) == 0xffff)
+#endif
+
+#ifdef _GNU_SOURCE
+int ptsname_r(int, char *, size_t);
+char *ecvt(double, int, int *, int *);
+char *fcvt(double, int, int *, int *);
+char *gcvt(double, int, char *);
+struct __locale_struct;
+float strtof_l(const char *__restrict, char **__restrict, struct __locale_struct *);
+double strtod_l(const char *__restrict, char **__restrict, struct __locale_struct *);
+long double strtold_l(const char *__restrict, char **__restrict, struct __locale_struct *);
+#endif
+
+#if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)
+#define mkstemp64 mkstemp
+#define mkostemp64 mkostemp
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define mkstemps64 mkstemps
+#define mkostemps64 mkostemps
+#endif
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif