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

fusl/src/internal/pthread_impl.h

+#ifndef _PTHREAD_IMPL_H
+#define _PTHREAD_IMPL_H
+
+#include <pthread.h>
+#include <signal.h>
+#include <errno.h>
+#include <limits.h>
+#include "libc.h"
+#include "syscall.h"
+#include "atomic.h"
+#include "futex.h"
+
+#define pthread __pthread
+
+struct pthread {
+        struct pthread *self;
+        void **dtv, *unused1, *unused2;
+        uintptr_t sysinfo;
+        uintptr_t canary, canary2;
+        pid_t tid, pid;
+        int tsd_used, errno_val;
+        volatile int cancel, canceldisable, cancelasync;
+        int detached;
+        unsigned char *map_base;
+        size_t map_size;
+        void *stack;
+        size_t stack_size;
+        void *start_arg;
+        void *(*start)(void *);
+        void *result;
+        struct __ptcb *cancelbuf;
+        void **tsd;
+        pthread_attr_t attr;
+        volatile int dead;
+        struct {
+                volatile void *volatile head;
+                long off;
+                volatile void *volatile pending;
+        } robust_list;
+        int unblock_cancel;
+        volatile int timer_id;
+        locale_t locale;
+        volatile int killlock[2];
+        volatile int exitlock[2];
+        volatile int startlock[2];
+        unsigned long sigmask[_NSIG/8/sizeof(long)];
+        char *dlerror_buf;
+        int dlerror_flag;
+        void *stdio_locks;
+        uintptr_t canary_at_end;
+        void **dtv_copy;
+};
+
+struct __timer {
+        int timerid;
+        pthread_t thread;
+};
+
+#define __SU (sizeof(size_t)/sizeof(int))
+
+#define _a_stacksize __u.__s[0]
+#define _a_guardsize __u.__s[1]
+#define _a_stackaddr __u.__s[2]
+#define _a_detach __u.__i[3*__SU+0]
+#define _a_sched __u.__i[3*__SU+1]
+#define _a_policy __u.__i[3*__SU+2]
+#define _a_prio __u.__i[3*__SU+3]
+#define _m_type __u.__i[0]
+#define _m_lock __u.__vi[1]
+#define _m_waiters __u.__vi[2]
+#define _m_prev __u.__p[3]
+#define _m_next __u.__p[4]
+#define _m_count __u.__i[5]
+#define _c_shared __u.__p[0]
+#define _c_seq __u.__vi[2]
+#define _c_waiters __u.__vi[3]
+#define _c_clock __u.__i[4]
+#define _c_lock __u.__vi[8]
+#define _c_head __u.__p[1]
+#define _c_tail __u.__p[5]
+#define _rw_lock __u.__vi[0]
+#define _rw_waiters __u.__vi[1]
+#define _rw_shared __u.__i[2]
+#define _b_lock __u.__vi[0]
+#define _b_waiters __u.__vi[1]
+#define _b_limit __u.__i[2]
+#define _b_count __u.__vi[3]
+#define _b_waiters2 __u.__vi[4]
+#define _b_inst __u.__p[3]
+
+#include "pthread_arch.h"
+
+#ifndef CANARY
+#define CANARY canary
+#endif
+
+#ifndef DTP_OFFSET
+#define DTP_OFFSET 0
+#endif
+
+#define SIGTIMER 32
+#define SIGCANCEL 33
+#define SIGSYNCCALL 34
+
+#define SIGALL_SET ((sigset_t *)(const unsigned long long [2]){ -1,-1 })
+#define SIGPT_SET \
+        ((sigset_t *)(const unsigned long [_NSIG/8/sizeof(long)]){ \
+        [sizeof(long)==4] = 3UL<<(32*(sizeof(long)>4)) })
+#define SIGTIMER_SET \
+        ((sigset_t *)(const unsigned long [_NSIG/8/sizeof(long)]){ \
+         0x80000000 })
+
+pthread_t __pthread_self_init(void);
+
+int __clone(int (*)(void *), void *, int, void *, ...);
+int __set_thread_area(void *);
+int __libc_sigaction(int, const struct sigaction *, struct sigaction *);
+int __libc_sigprocmask(int, const sigset_t *, sigset_t *);
+void __lock(volatile int *);
+void __unmapself(void *, size_t);
+
+void __vm_wait(void);
+void __vm_lock(void);
+void __vm_unlock(void);
+
+int __timedwait(volatile int *, int, clockid_t, const struct timespec *, int);
+int __timedwait_cp(volatile int *, int, clockid_t, const struct timespec *, int);
+void __wait(volatile int *, volatile int *, int, int);
+static inline void __wake(volatile void *addr, int cnt, int priv)
+{
+        if (priv) priv = 128;
+        if (cnt<0) cnt = INT_MAX;
+        __syscall(SYS_futex, addr, FUTEX_WAKE|priv, cnt) != -ENOSYS ||
+        __syscall(SYS_futex, addr, FUTEX_WAKE, cnt);
+}
+
+void __acquire_ptc(void);
+void __release_ptc(void);
+void __inhibit_ptc(void);
+
+void __block_all_sigs(void *);
+void __block_app_sigs(void *);
+void __restore_sigs(void *);
+
+#define DEFAULT_STACK_SIZE 81920
+#define DEFAULT_GUARD_SIZE PAGE_SIZE
+
+#define __ATTRP_C11_THREAD ((void*)(uintptr_t)-1)
+
+#endif