media-libs/opencv/files/opencv-2.3.0-atomic.patch

Patch to fix build errors when using libc++ as libc++
does not provide the header <ext/atomicity.h>.
This is a backport from upstream OpenCV where the issue is
already fixed.

diff -Nuar old/OpenCV-2.3.0/modules/core/include/opencv2/core/operations.hpp new/OpenCV-2.3.0/modules/core/include/opencv2/core/operations.hpp
--- old/OpenCV-2.3.0/modules/core/include/opencv2/core/operations.hpp
+++ new/OpenCV-2.3.0/modules/core/include/opencv2/core/operations.hpp
@@ -51,35 +51,28 @@
 #ifdef __cplusplus
 
 /////// exchange-add operation for atomic operations on reference counters ///////
-#ifdef __GNUC__
-    
-  #if __GNUC__*10 + __GNUC_MINOR__ >= 42
-
-    #if !defined WIN32 && (defined __i486__ || defined __i586__ || \
-        defined __i686__ || defined __MMX__ || defined __SSE__  || defined __ppc__)
-      #define CV_XADD __sync_fetch_and_add
-    #else
-      #include <ext/atomicity.h>
-      #define CV_XADD __gnu_cxx::__exchange_and_add
-    #endif
-
-  #else
-    #include <bits/atomicity.h>
-    #if __GNUC__*10 + __GNUC_MINOR__ >= 34
-      #define CV_XADD __gnu_cxx::__exchange_and_add
-    #else
-      #define CV_XADD __exchange_and_add
-    #endif
-  #endif
-    
-#elif defined WIN32 || defined _WIN32
-  #include <intrin.h>
-  #define CV_XADD(addr,delta) _InterlockedExchangeAdd((long volatile*)(addr), (delta))
+#ifdef CV_XADD
+  // allow to use user-defined macro
+#elif defined __GNUC__ || defined __clang__
+#  if defined __clang__ && __clang_major__ >= 3 && !defined __ANDROID__ && !defined __EMSCRIPTEN__ && !defined(__CUDACC__)
+#    ifdef __ATOMIC_ACQ_REL
+#      define CV_XADD(addr, delta) __c11_atomic_fetch_add((_Atomic(int)*)(addr), delta, __ATOMIC_ACQ_REL)
+#    else
+#      define CV_XADD(addr, delta) __atomic_fetch_add((_Atomic(int)*)(addr), delta, 4)
+#    endif
+#  else
+#    if defined __ATOMIC_ACQ_REL && !defined __clang__
+       // version for gcc >= 4.7
+#      define CV_XADD(addr, delta) (int)__atomic_fetch_add((unsigned*)(addr), (unsigned)(delta), __ATOMIC_ACQ_REL)
+#    else
+#      define CV_XADD(addr, delta) (int)__sync_fetch_and_add((unsigned*)(addr), (unsigned)(delta))
+#    endif
+#  endif
+#elif defined _MSC_VER && !defined RC_INVOKED
+#  include <intrin.h>
+#  define CV_XADD(addr, delta) (int)_InterlockedExchangeAdd((long volatile*)addr, delta)
 #else
-
-  template<typename _Tp> static inline _Tp CV_XADD(_Tp* addr, _Tp delta)
-  { int tmp = *addr; *addr += delta; return tmp; }
-    
+   CV_INLINE CV_XADD(int* addr, int delta) { int tmp = *addr; *addr += delta; return tmp; }
 #endif
 
 #include <limits>