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

fusl/crt/rcrt1.c

Index: fusl/crt/rcrt1.c
diff --git a/fusl/crt/rcrt1.c b/fusl/crt/rcrt1.c
new file mode 100644
index 0000000000000000000000000000000000000000..9be117fdaa5416381c70f3c751c21473b40c9497
--- /dev/null
+++ b/fusl/crt/rcrt1.c
@@ -0,0 +1,16 @@
+#define SHARED
+#define START "_start"
+#define _dlstart_c _start_c
+#include "../src/ldso/dlstart.c"
+
+int main();
+void _init() __attribute__((weak));
+void _fini() __attribute__((weak));
+_Noreturn int __libc_start_main(int (*)(), int, char **,
+	void (*)(), void(*)(), void(*)());
+
+__attribute__((__visibility__("hidden")))
+_Noreturn void __dls2(unsigned char *base, size_t *sp)
+{
+	__libc_start_main(main, *sp, (void *)(sp+1), _init, _fini, 0);
+}