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

fusl/arch/aarch64/bits/user.h

Index: fusl/arch/aarch64/bits/user.h
diff --git a/fusl/arch/aarch64/bits/user.h b/fusl/arch/aarch64/bits/user.h
new file mode 100644
index 0000000000000000000000000000000000000000..d12cdf7fe5c5d8f32494b8a9660591061cb4427d
--- /dev/null
+++ b/fusl/arch/aarch64/bits/user.h
@@ -0,0 +1,16 @@
+struct user_regs_struct {
+	unsigned long long regs[31];
+	unsigned long long sp;
+	unsigned long long pc;
+	unsigned long long pstate;
+};
+
+struct user_fpsimd_struct {
+	long double vregs[32];
+	unsigned int fpsr;
+	unsigned int fpcr;
+};
+
+#define ELF_NREG 34
+typedef unsigned long elf_greg_t, elf_gregset_t[ELF_NREG];
+typedef struct user_fpsimd_struct elf_fpregset_t;