Merge pull request opencv#14252 from balachandarsv:master-mac-openvino-support

* Mac support for op inference engine

Adding condition to check for mac and add corresponding libraries

* Adding mac support in test cases

Author: balachandarsv

modules/dnn/src/op_inf_engine.cpp

@@ -784,6 +784,8 @@ void InfEngineBackendNet::initPlugin(InferenceEngine::ICNNNetwork& net)
                         continue;
     #ifdef _WIN32
                     std::string libName = "cpu_extension" + suffixes[i] + ".dll";
+    #elif defined(__APPLE__)
+                    std::string libName = "libcpu_extension" + suffixes[i] + ".dylib";
     #else
                     std::string libName = "libcpu_extension" + suffixes[i] + ".so";
     #endif  // _WIN32

modules/dnn/test/test_ie_models.cpp

@@ -172,6 +172,8 @@ void runIE(Target target, const std::string& xmlPath, const std::string& binPath
                     continue;
 #ifdef _WIN32
                 std::string libName = "cpu_extension" + suffixes[i] + ".dll";
+#elif defined(__APPLE__)
+                std::string libName = "libcpu_extension" + suffixes[i] + ".dylib";
 #else
                 std::string libName = "libcpu_extension" + suffixes[i] + ".so";
 #endif  // _WIN32