commit 69e9378eb86357d4361322256d5d5a39ff4a592d
Author: q66 <daniel@octaforge.org>
Date:   Fri Jan 10 13:04:37 2020 +0100

    use __atomic builtins instead of legacy __sync
    
    This allows for 64-bit atomic ops on platforms that don't natively
    support them such as armv6 and ppc32.

diff --git atomic/unix/builtins64.c atomic/unix/builtins64.c
index 4a4b685..90b5c5e 100644
--- atomic/unix/builtins64.c
+++ atomic/unix/builtins64.c
@@ -30,35 +30,34 @@ APR_DECLARE(void) apr_atomic_set64(volatile apr_uint64_t *mem, apr_uint64_t val)
 
 APR_DECLARE(apr_uint64_t) apr_atomic_add64(volatile apr_uint64_t *mem, apr_uint64_t val)
 {
-    return __sync_fetch_and_add(mem, val);
+    return __atomic_fetch_add(mem, val, __ATOMIC_SEQ_CST);
 }
 
 APR_DECLARE(void) apr_atomic_sub64(volatile apr_uint64_t *mem, apr_uint64_t val)
 {
-    __sync_fetch_and_sub(mem, val);
+    __atomic_fetch_sub(mem, val, __ATOMIC_SEQ_CST);
 }
 
 APR_DECLARE(apr_uint64_t) apr_atomic_inc64(volatile apr_uint64_t *mem)
 {
-    return __sync_fetch_and_add(mem, 1);
+    return __atomic_fetch_add(mem, 1, __ATOMIC_SEQ_CST);
 }
 
 APR_DECLARE(int) apr_atomic_dec64(volatile apr_uint64_t *mem)
 {
-    return __sync_sub_and_fetch(mem, 1);
+    return (int)__atomic_sub_fetch(mem, 1, __ATOMIC_SEQ_CST);
 }
 
 APR_DECLARE(apr_uint64_t) apr_atomic_cas64(volatile apr_uint64_t *mem, apr_uint64_t with,
                                            apr_uint64_t cmp)
 {
-    return __sync_val_compare_and_swap(mem, cmp, with);
+    __atomic_compare_exchange_n(mem, &cmp, with, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+    return cmp;
 }
 
 APR_DECLARE(apr_uint64_t) apr_atomic_xchg64(volatile apr_uint64_t *mem, apr_uint64_t val)
 {
-    __sync_synchronize();
-
-    return __sync_lock_test_and_set(mem, val);
+    return __atomic_exchange_n(mem, val, __ATOMIC_SEQ_CST);
 }
 
 #endif /* USE_ATOMICS_BUILTINS */