Fix C++11 compilation of atomic

Close #14569

include/vlc_atomic.h

@@ -32,6 +32,78 @@
 /*** Native C11 atomics ***/
 #  include <stdatomic.h>
 
+# elif defined (__cplusplus) && (__cplusplus >= 201103L)
+#   include <atomic>
+using std::atomic_is_lock_free;
+using std::atomic_init;
+using std::atomic_store;
+using std::atomic_store_explicit;
+using std::atomic_load;
+using std::atomic_load_explicit;
+using std::atomic_exchange;
+using std::atomic_exchange_explicit;
+using std::atomic_compare_exchange_strong;
+using std::atomic_compare_exchange_strong_explicit;
+using std::atomic_compare_exchange_weak;
+using std::atomic_compare_exchange_weak_explicit;
+using std::atomic_fetch_add;
+using std::atomic_fetch_add_explicit;
+using std::atomic_fetch_sub;
+using std::atomic_fetch_sub_explicit;
+using std::atomic_fetch_or;
+using std::atomic_fetch_or_explicit;
+using std::atomic_fetch_xor;
+using std::atomic_fetch_xor_explicit;
+using std::atomic_fetch_and;
+using std::atomic_fetch_and_explicit;
+using std::atomic_thread_fence;
+using std::atomic_signal_fence;
+
+using std::memory_order;
+using std::memory_order_relaxed;
+using std::memory_order_consume;
+using std::memory_order_release;
+using std::memory_order_acq_rel;
+using std::memory_order_seq_cst;
+
+using std::atomic_flag;
+using std::atomic_bool;
+using std::atomic_char;
+using std::atomic_schar;
+using std::atomic_uchar;
+using std::atomic_short;
+using std::atomic_ushort;
+using std::atomic_int;
+using std::atomic_uint;
+using std::atomic_long;
+using std::atomic_ulong;
+using std::atomic_llong;
+using std::atomic_ullong;
+//using std::atomic_char16_t;
+//using std::atomic_char32_t;
+using std::atomic_wchar_t;
+using std::atomic_int_least8_t;
+using std::atomic_uint_least8_t;
+using std::atomic_int_least16_t;
+using std::atomic_uint_least16_t;
+using std::atomic_int_least32_t;
+using std::atomic_uint_least32_t;
+using std::atomic_int_least64_t;
+using std::atomic_uint_least64_t;
+using std::atomic_int_fast8_t;
+using std::atomic_uint_fast8_t;
+using std::atomic_int_fast16_t;
+using std::atomic_uint_fast16_t;
+using std::atomic_int_fast32_t;
+using std::atomic_uint_fast32_t;
+using std::atomic_int_fast64_t;
+using std::atomic_uint_fast64_t;
+using std::atomic_intptr_t;
+using std::atomic_uintptr_t;
+using std::atomic_size_t;
+using std::atomic_ptrdiff_t;
+using std::atomic_intmax_t;
+using std::atomic_uintmax_t;
 # else
 
 #  define ATOMIC_FLAG_INIT false