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

fusl/arch/x86_64/syscall_arch.h

+#define __SYSCALL_LL_E(x) (x)
+#define __SYSCALL_LL_O(x) (x)
+
+static __inline long __syscall0(long n)
+{
+        unsigned long ret;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n) : "rcx", "r11", "memory");
+        return ret;
+}
+
+static __inline long __syscall1(long n, long a1)
+{
+        unsigned long ret;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1) : "rcx", "r11", "memory");
+        return ret;
+}
+
+static __inline long __syscall2(long n, long a1, long a2)
+{
+        unsigned long ret;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2)
+                                                  : "rcx", "r11", "memory");
+        return ret;
+}
+
+static __inline long __syscall3(long n, long a1, long a2, long a3)
+{
+        unsigned long ret;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
+                                                  "d"(a3) : "rcx", "r11", "memory");
+        return ret;
+}
+
+static __inline long __syscall4(long n, long a1, long a2, long a3, long a4)
+{
+        unsigned long ret;
+        register long r10 __asm__("r10") = a4;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
+                                                  "d"(a3), "r"(r10): "rcx", "r11", "memory");
+        return ret;
+}
+
+static __inline long __syscall5(long n, long a1, long a2, long a3, long a4, long a5)
+{
+        unsigned long ret;
+        register long r10 __asm__("r10") = a4;
+        register long r8 __asm__("r8") = a5;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
+                                                  "d"(a3), "r"(r10), "r"(r8) : "rcx", "r11", "memory");
+        return ret;
+}
+
+static __inline long __syscall6(long n, long a1, long a2, long a3, long a4, long a5, long a6)
+{
+        unsigned long ret;
+        register long r10 __asm__("r10") = a4;
+        register long r8 __asm__("r8") = a5;
+        register long r9 __asm__("r9") = a6;
+        __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
+                                                  "d"(a3), "r"(r10), "r"(r8), "r"(r9) : "rcx", "r11", "memory");
+        return ret;
+}
+
+#define VDSO_USEFUL
+#define VDSO_CGT_SYM "__vdso_clock_gettime"
+#define VDSO_CGT_VER "LINUX_2.6"