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

fusl/arch/i386/atomic.h

+#ifndef _INTERNAL_ATOMIC_H
+#define _INTERNAL_ATOMIC_H
+
+#include <stdint.h>
+
+static inline int a_ctz_64(uint64_t x)
+{
+        int r;
+        __asm__( "bsf %1,%0 ; jnz 1f ; bsf %2,%0 ; addl $32,%0\n1:"
+                : "=&r"(r) : "r"((unsigned)x), "r"((unsigned)(x>>32)) );
+        return r;
+}
+
+static inline int a_ctz_l(unsigned long x)
+{
+        long r;
+        __asm__( "bsf %1,%0" : "=r"(r) : "r"(x) );
+        return r;
+}
+
+static inline void a_and_64(volatile uint64_t *p, uint64_t v)
+{
+        __asm__( "lock ; andl %1, (%0) ; lock ; andl %2, 4(%0)"
+                : : "r"((long *)p), "r"((unsigned)v), "r"((unsigned)(v>>32)) : "memory" );
+}
+
+static inline void a_or_64(volatile uint64_t *p, uint64_t v)
+{
+        __asm__( "lock ; orl %1, (%0) ; lock ; orl %2, 4(%0)"
+                : : "r"((long *)p), "r"((unsigned)v), "r"((unsigned)(v>>32)) : "memory" );
+}
+
+static inline void a_or_l(volatile void *p, long v)
+{
+        __asm__( "lock ; orl %1, %0"
+                : "=m"(*(long *)p) : "r"(v) : "memory" );
+}
+
+static inline void *a_cas_p(volatile void *p, void *t, void *s)
+{
+        __asm__( "lock ; cmpxchg %3, %1"
+                : "=a"(t), "=m"(*(long *)p) : "a"(t), "r"(s) : "memory" );
+        return t;
+}
+
+static inline int a_cas(volatile int *p, int t, int s)
+{
+        __asm__( "lock ; cmpxchg %3, %1"
+                : "=a"(t), "=m"(*p) : "a"(t), "r"(s) : "memory" );
+        return t;
+}
+
+static inline void a_or(volatile int *p, int v)
+{
+        __asm__( "lock ; orl %1, %0"
+                : "=m"(*p) : "r"(v) : "memory" );
+}
+
+static inline void a_and(volatile int *p, int v)
+{
+        __asm__( "lock ; andl %1, %0"
+                : "=m"(*p) : "r"(v) : "memory" );
+}
+
+static inline int a_swap(volatile int *x, int v)
+{
+        __asm__( "xchg %0, %1" : "=r"(v), "=m"(*x) : "0"(v) : "memory" );
+        return v;
+}
+
+#define a_xchg a_swap
+
+static inline int a_fetch_add(volatile int *x, int v)
+{
+        __asm__( "lock ; xadd %0, %1" : "=r"(v), "=m"(*x) : "0"(v) : "memory" );
+        return v;
+}
+
+static inline void a_inc(volatile int *x)
+{
+        __asm__( "lock ; incl %0" : "=m"(*x) : "m"(*x) : "memory" );
+}
+
+static inline void a_dec(volatile int *x)
+{
+        __asm__( "lock ; decl %0" : "=m"(*x) : "m"(*x) : "memory" );
+}
+
+static inline void a_store(volatile int *p, int x)
+{
+        __asm__( "movl %1, %0 ; lock ; orl $0,(%%esp)" : "=m"(*p) : "r"(x) : "memory" );
+}
+
+static inline void a_spin()
+{
+        __asm__ __volatile__( "pause" : : : "memory" );
+}
+
+static inline void a_barrier()
+{
+        __asm__ __volatile__( "" : : : "memory" );
+}
+
+static inline void a_crash()
+{
+        __asm__ __volatile__( "hlt" : : : "memory" );
+}
+
+
+#endif