cmake/re-config: on some platforms linking atomic is needed

cmake/re-config.cmake

@@ -2,6 +2,7 @@ include(CheckIncludeFile)
 include(CheckFunctionExists)
 include(CheckSymbolExists)
 include(CheckTypeSize)
+include(CheckCXXSourceCompiles)
 
 option(USE_MBEDTLS "Enable MbedTLS" OFF)
 
@@ -214,3 +215,34 @@ if(NOT ${CMAKE_BUILD_TYPE} MATCHES "[Rr]el")
     set(CMAKE_ENABLE_EXPORTS ON)
   endif()
 endif()
+
+# Testing Atomic
+
+enable_language(CXX)
+
+set(ATOMIC32_TEST_CODE "
+    #include <atomic>
+    #include <stdint.h>
+    int main() {
+        std::atomic<int32_t> x;
+        x.store(1);
+        x--;
+        return x.load();
+    }")
+
+set(ATOMIC64_TEST_CODE "
+    #include <atomic>
+    #include <stdint.h>
+    int main() {
+        std::atomic<int64_t> x;
+        x.store(1);
+        x--;
+        return x.load();
+    }")
+
+check_cxx_source_compiles("${ATOMIC32_TEST_CODE}" atomic32_test)
+check_cxx_source_compiles("${ATOMIC64_TEST_CODE}" atomic64_test)
+
+if(NOT atomic32_test OR NOT atomic64_test)
+  set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES} atomic)
+endif()