change compile to gcc on Apple as default

.vscode/.cmaketools.json

+{
+  "variant": {
+    "label": "Release",
+    "keywordSettings": {
+      "buildType": "release"
+    },
+    "description": "Enable optimizations, omit debug info"
+  },
+  "activeEnvironments": []
+}
\ No newline at end of file

CMakeLists.txt

 cmake_minimum_required(VERSION 2.8)
 
+if(APPLE)
+    SET(CMAKE_CXX_COMPILER "g++-6")
+    SET(CMAKE_C_COMPILER "gcc-6")
+endif()
+
 PROJECT(lightgbm)
 
 OPTION(USE_MPI "MPI based parallel learning" OFF)
@@ -13,6 +18,7 @@ else()
     ADD_DEFINITIONS(-DUSE_SOCKET)
 endif(USE_MPI)
 
+
 find_package(OpenMP REQUIRED)
 
 SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")