change errno to error to avoid confusion

include/zinnia/syscall.h

@@ -4,7 +4,7 @@
 
 struct syscall_ret {
     uintptr_t value;
-    int errno;
+    int error;
 };
 
 struct syscall {

include/zinnia/syscall_list.inc

@@ -1,5 +1,5 @@
 #ifndef SYSCALL_DECLARE
-#define SYSCALL_DECLARE(number, name, num_args) extern void sys_##name(...);
+#define SYSCALL_DECLARE(number, name, num_args)
 #endif
 
 SYSCALL_DECLARE(0, exit, 1)