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

fusl/src/unistd/readlink.c

Index: fusl/src/unistd/readlink.c
diff --git a/fusl/src/unistd/readlink.c b/fusl/src/unistd/readlink.c
new file mode 100644
index 0000000000000000000000000000000000000000..a152d52492ed775d3d8fd57125423e461bfb20d8
--- /dev/null
+++ b/fusl/src/unistd/readlink.c
@@ -0,0 +1,12 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include "syscall.h"
+
+ssize_t readlink(const char *restrict path, char *restrict buf, size_t bufsize)
+{
+#ifdef SYS_readlink
+	return syscall(SYS_readlink, path, buf, bufsize);
+#else
+	return syscall(SYS_readlinkat, AT_FDCWD, path, buf, bufsize);
+#endif
+}