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

fusl/arch/arm/bits/user.h

+typedef struct user_fpregs {
+        struct fp_reg {
+                unsigned sign1:1;
+                unsigned unused:15;
+                unsigned sign2:1;
+                unsigned exponent:14;
+                unsigned j:1;
+                unsigned mantissa1:31;
+                unsigned mantissa0:32;
+        } fpregs[8];
+        unsigned fpsr:32;
+        unsigned fpcr:32;
+        unsigned char ftype[8];
+        unsigned int init_flag;
+} elf_fpregset_t;
+
+struct user_regs {
+        unsigned long uregs[18];
+};
+#define ELF_NGREG 18
+typedef unsigned long elf_greg_t, elf_gregset_t[ELF_NGREG];
+
+struct user {
+        struct user_regs regs;
+        int u_fpvalid;
+        unsigned long u_tsize, u_dsize, u_ssize;
+        unsigned long start_code, start_stack;
+        long signal;
+        int reserved;
+        struct user_regs *u_ar0;
+        unsigned long magic;
+        char u_comm[32];
+        int u_debugreg[8];
+        struct user_fpregs u_fp;
+        struct user_fpregs *u_fp0;
+};