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

fusl/src/stdio/rename.c

Index: fusl/src/stdio/rename.c
diff --git a/fusl/src/stdio/rename.c b/fusl/src/stdio/rename.c
new file mode 100644
index 0000000000000000000000000000000000000000..04c90c01343a4b84beb5cf56b348e5d5041905ed
--- /dev/null
+++ b/fusl/src/stdio/rename.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include "syscall.h"
+
+int rename(const char *old, const char *new)
+{
+#ifdef SYS_rename
+	return syscall(SYS_rename, old, new);
+#else
+	return syscall(SYS_renameat, AT_FDCWD, old, AT_FDCWD, new);
+#endif
+}