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

fusl/src/env/__reset_tls.c

+#include <string.h>
+#include "pthread_impl.h"
+#include "libc.h"
+
+void __reset_tls()
+{
+        pthread_t self = __pthread_self();
+        struct tls_module *p;
+        size_t i, n = (size_t)self->dtv[0];
+        if (n) for (p=libc.tls_head, i=1; i<=n; i++, p=p->next) {
+                if (!self->dtv[i]) continue;
+                memcpy(self->dtv[i], p->image, p->len);
+                memset((char *)self->dtv[i]+p->len, 0,
+                        p->size - p->len);
+        }
+}