Merge pull request #2936 from martonmiklos/add_compilation_db_to_qt_gitignore

Add compilation db to Qt gitignore

Qt.gitignore

@@ -41,3 +41,6 @@ target_wrapper.*
 
 # QtCreator CMake
 CMakeLists.txt.user*
+
+# QtCreator 4.8< compilation database 
+compile_commands.json