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

fusl/src/stdio/ftrylockfile.c

+#include "stdio_impl.h"
+#include "pthread_impl.h"
+#include <limits.h>
+
+void __do_orphaned_stdio_locks()
+{
+        FILE *f;
+        for (f=__pthread_self()->stdio_locks; f; f=f->next_locked)
+                a_store(&f->lock, 0x40000000);
+}
+
+void __unlist_locked_file(FILE *f)
+{
+        if (f->lockcount) {
+                if (f->next_locked) f->next_locked->prev_locked = f->prev_locked;
+                if (f->prev_locked) f->prev_locked->next_locked = f->next_locked;
+                else __pthread_self()->stdio_locks = f->next_locked;
+        }
+}
+
+int ftrylockfile(FILE *f)
+{
+        pthread_t self = __pthread_self();
+        int tid = self->tid;
+        if (f->lock == tid) {
+                if (f->lockcount == LONG_MAX)
+                        return -1;
+                f->lockcount++;
+                return 0;
+        }
+        if (f->lock < 0) f->lock = 0;
+        if (f->lock || a_cas(&f->lock, 0, tid))
+                return -1;
+        f->lockcount = 1;
+        f->prev_locked = 0;
+        f->next_locked = self->stdio_locks;
+        if (f->next_locked) f->next_locked->prev_locked = f;
+        self->stdio_locks = f;
+        return 0;
+}