fix build on iOS

Author: kulikjak

configure

@@ -5335,7 +5335,7 @@ AC_CHECK_FUNCS([ \
   lockf lstat lutimes madvise mbrtowc memrchr mkdirat mkfifo mkfifoat \
   mknod mknodat mktime mmap mremap nice openat opendir pathconf pause pipe \
   pipe2 plock poll ppoll posix_fadvise posix_fallocate posix_openpt posix_spawn posix_spawnp \
-  posix_spawn_file_actions_addchdir_np posix_spawn_file_actions_addclosefrom_np \
+  posix_spawn_file_actions_addclosefrom_np \
   pread preadv preadv2 process_vm_readv \
   pthread_cond_timedwait_relative_np pthread_condattr_setclock pthread_init \
   pthread_kill pthread_get_name_np pthread_getname_np pthread_set_name_np \
@@ -5371,7 +5371,7 @@ fi
 # header definition prevents usage - autoconf doesn't use the headers), or
 # raise an error if used at runtime. Force these symbols off.
 if test "$ac_sys_system" != "iOS" ; then
-  AC_CHECK_FUNCS([getentropy getgroups system])
+  AC_CHECK_FUNCS([getentropy getgroups posix_spawn_file_actions_addchdir_np system])
 fi
 
 AC_CHECK_DECL([dirfd],