[fusl] Remove code for unsupported architectures

fusl/arch/i386/atomic_arch.h

-#define a_cas a_cas
-static inline int a_cas(volatile int* p, int t, int s) {
-  __asm__ __volatile__("lock ; cmpxchg %3, %1"
-                       : "=a"(t), "=m"(*p)
-                       : "a"(t), "r"(s)
-                       : "memory");
-  return t;
-}
-
-#define a_swap a_swap
-static inline int a_swap(volatile int* p, int v) {
-  __asm__ __volatile__("xchg %0, %1" : "=r"(v), "=m"(*p) : "0"(v) : "memory");
-  return v;
-}
-
-#define a_fetch_add a_fetch_add
-static inline int a_fetch_add(volatile int* p, int v) {
-  __asm__ __volatile__("lock ; xadd %0, %1"
-                       : "=r"(v), "=m"(*p)
-                       : "0"(v)
-                       : "memory");
-  return v;
-}
-
-#define a_and a_and
-static inline void a_and(volatile int* p, int v) {
-  __asm__ __volatile__("lock ; and %1, %0" : "=m"(*p) : "r"(v) : "memory");
-}
-
-#define a_or a_or
-static inline void a_or(volatile int* p, int v) {
-  __asm__ __volatile__("lock ; or %1, %0" : "=m"(*p) : "r"(v) : "memory");
-}
-
-#define a_inc a_inc
-static inline void a_inc(volatile int* p) {
-  __asm__ __volatile__("lock ; incl %0" : "=m"(*p) : "m"(*p) : "memory");
-}
-
-#define a_dec a_dec
-static inline void a_dec(volatile int* p) {
-  __asm__ __volatile__("lock ; decl %0" : "=m"(*p) : "m"(*p) : "memory");
-}
-
-#define a_store a_store
-static inline void a_store(volatile int* p, int x) {
-  __asm__ __volatile__("mov %1, %0 ; lock ; orl $0,(%%esp)"
-                       : "=m"(*p)
-                       : "r"(x)
-                       : "memory");
-}
-
-#define a_barrier a_barrier
-static inline void a_barrier() {
-  __asm__ __volatile__("" : : : "memory");
-}
-
-#define a_pause a_pause
-static inline void a_spin() {
-  __asm__ __volatile__("pause" : : : "memory");
-}
-
-#define a_crash a_crash
-static inline void a_crash() {
-  __asm__ __volatile__("hlt" : : : "memory");
-}
-
-#define a_ctz_64 a_ctz_64
-static inline int a_ctz_64(uint64_t x) {
-  int r;
-  __asm__("bsf %1,%0 ; jnz 1f ; bsf %2,%0 ; add $32,%0\n1:"
-          : "=&r"(r)
-          : "r"((unsigned)x), "r"((unsigned)(x >> 32)));
-  return r;
-}
-
-#define a_ctz_l a_ctz_l
-static inline int a_ctz_l(unsigned long x) {
-  long r;
-  __asm__("bsf %1,%0" : "=r"(r) : "r"(x));
-  return r;
-}