1. ffmpeg
  2. Commit 3359eede8fc5f6b34b76138a44cf1b2ea45fe0a5
Browse code

Add a compat stdatomic.h implementation based on GCC atomics

Adapted from the code by Rémi Denis-Courmont from VLC

This merges libav commit 4e928ef340ac20325f529d92fcbc51e768085358.

Signed-off-by: Wan-Teh Chang <wtc@google.com>
Reviewed-by: wm4 <nfxjfg@googlemail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

Anton Khirnov authored on 2016/11/29 06:24:22
Showing 2 changed files
compat/atomics/gcc/stdatomic.h
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+/*
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+ * This file is part of FFmpeg.
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+ *
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+ * FFmpeg is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU Lesser General Public
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+ * License as published by the Free Software Foundation; either
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+ * version 2.1 of the License, or (at your option) any later version.
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+ *
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+ * FFmpeg is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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+ * Lesser General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU Lesser General Public
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+ * License along with FFmpeg; if not, write to the Free Software
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+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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+ */
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+
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+/*
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+ * based on vlc_atomic.h from VLC
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+ * Copyright (C) 2010 Rémi Denis-Courmont
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+ */
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+
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+#ifndef FFMPEG_COMPAT_ATOMICS_GCC_STDATOMIC_H
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+#define FFMPEG_COMPAT_ATOMICS_GCC_STDATOMIC_H
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+
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+#include <stddef.h>
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+#include <stdint.h>
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+
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+#define ATOMIC_FLAG_INIT 0
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+
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+#define ATOMIC_VAR_INIT(value) (value)
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+
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+#define atomic_init(obj, value) \
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+do {                            \
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+    *(obj) = (value);           \
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+} while(0)
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+
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+#define kill_dependency(y) ((void)0)
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+
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+#define atomic_thread_fence(order) \
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+    __sync_synchronize()
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+
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+#define atomic_signal_fence(order) \
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+    ((void)0)
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+
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+#define atomic_is_lock_free(obj) 0
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+
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+typedef         _Bool      atomic_flag;
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+typedef         _Bool      atomic_bool;
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+typedef          char      atomic_char;
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+typedef   signed char      atomic_schar;
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+typedef unsigned char      atomic_uchar;
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+typedef          short     atomic_short;
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+typedef unsigned short     atomic_ushort;
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+typedef          int       atomic_int;
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+typedef unsigned int       atomic_uint;
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+typedef          long      atomic_long;
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+typedef unsigned long      atomic_ulong;
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+typedef          long long atomic_llong;
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+typedef unsigned long long atomic_ullong;
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+typedef          wchar_t   atomic_wchar_t;
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+typedef       int_least8_t atomic_int_least8_t;
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+typedef      uint_least8_t atomic_uint_least8_t;
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+typedef      int_least16_t atomic_int_least16_t;
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+typedef     uint_least16_t atomic_uint_least16_t;
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+typedef      int_least32_t atomic_int_least32_t;
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+typedef     uint_least32_t atomic_uint_least32_t;
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+typedef      int_least64_t atomic_int_least64_t;
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+typedef     uint_least64_t atomic_uint_least64_t;
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+typedef       int_fast8_t atomic_int_fast8_t;
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+typedef      uint_fast8_t atomic_uint_fast8_t;
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+typedef      int_fast16_t atomic_int_fast16_t;
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+typedef     uint_fast16_t atomic_uint_fast16_t;
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+typedef      int_fast32_t atomic_int_fast32_t;
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+typedef     uint_fast32_t atomic_uint_fast32_t;
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+typedef      int_fast64_t atomic_int_fast64_t;
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+typedef     uint_fast64_t atomic_uint_fast64_t;
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+typedef          intptr_t atomic_intptr_t;
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+typedef         uintptr_t atomic_uintptr_t;
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+typedef            size_t atomic_size_t;
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+typedef         ptrdiff_t atomic_ptrdiff_t;
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+typedef          intmax_t atomic_intmax_t;
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+typedef         uintmax_t atomic_uintmax_t;
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+
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+#define atomic_store(object, desired)   \
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+do {                                    \
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+    *(object) = (desired);              \
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+    __sync_synchronize();               \
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+} while (0)
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+
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+#define atomic_store_explicit(object, desired, order) \
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+    atomic_store(object, desired)
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+
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+#define atomic_load(object) \
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+    (__sync_synchronize(), *(object))
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+
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+#define atomic_load_explicit(object, order) \
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+    atomic_load(object)
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+
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+#define atomic_exchange(object, desired)                            \
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+({                                                                  \
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+    typeof(object) _obj = (object);                                 \
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+    typeof(*object) _old;                                           \
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+    do                                                              \
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+        _old = atomic_load(_obj);                                   \
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+    while (!__sync_bool_compare_and_swap(_obj, _old, (desired)));   \
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+    _old;                                                           \
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+})
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+
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+#define atomic_exchange_explicit(object, desired, order) \
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+    atomic_exchange(object, desired)
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+
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+#define atomic_compare_exchange_strong(object, expected, desired)   \
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+({                                                                  \
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+    typeof(object) _exp = (expected);                               \
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+    typeof(*object) _old = *_exp;                                   \
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+    *_exp = __sync_val_compare_and_swap((object), _old, (desired)); \
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+    *_exp == _old;                                                  \
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+})
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+
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+#define atomic_compare_exchange_strong_explicit(object, expected, desired, success, failure) \
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+    atomic_compare_exchange_strong(object, expected, desired)
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+
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+#define atomic_compare_exchange_weak(object, expected, desired) \
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+    atomic_compare_exchange_strong(object, expected, desired)
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+
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+#define atomic_compare_exchange_weak_explicit(object, expected, desired, success, failure) \
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+    atomic_compare_exchange_weak(object, expected, desired)
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+
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+#define atomic_fetch_add(object, operand) \
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+    __sync_fetch_and_add(object, operand)
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+
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+#define atomic_fetch_add_explicit(object, operand, order) \
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+    atomic_fetch_add(object, operand)
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+
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+#define atomic_fetch_sub(object, operand) \
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+    __sync_fetch_and_sub(object, operand)
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+
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+#define atomic_fetch_sub_explicit(object, operand, order) \
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+    atomic_fetch_sub(object, operand)
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+
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+#define atomic_fetch_or(object, operand) \
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+    __sync_fetch_and_or(object, operand)
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+
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+#define atomic_fetch_or_explicit(object, operand, order) \
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+    atomic_fetch_or(object, operand)
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+
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+#define atomic_fetch_xor(object, operand) \
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+    __sync_fetch_and_sub(object, operand)
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+
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+#define atomic_fetch_xor_explicit(object, operand, order) \
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+    atomic_fetch_sub(object, operand)
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+
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+#define atomic_fetch_and(object, operand) \
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+    __sync_fetch_and_and(object, operand)
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+
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+#define atomic_fetch_and_explicit(object, operand, order) \
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+    atomic_fetch_and(object, operand)
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+
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+#define atomic_flag_test_and_set(object) \
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+    atomic_exchange(object, 1)
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+
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+#define atomic_flag_test_and_set_explicit(object, order) \
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+    atomic_flag_test_and_set(object)
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+
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+#define atomic_flag_clear(object) \
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+    atomic_store(object, 0)
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+
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+#define atomic_flag_clear_explicit(object, order) \
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+    atomic_flag_clear(object)
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+
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+#endif /* FFMPEG_COMPAT_ATOMICS_GCC_STDATOMIC_H */
configure
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@@ -6381,6 +6381,12 @@ for thread in $THREADS_LIST; do
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     fi
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 done
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+if disabled stdatomic_h; then
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+    if enabled atomics_gcc; then
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+        add_cppflags '-I\$(SRC_PATH)/compat/atomics/gcc'
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+    fi
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+fi
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+
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 enabled zlib && add_cppflags -DZLIB_CONST
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 # conditional library dependencies, in linking order