Add define that makes QsLog to log via a separate thread.

This should avoid any lookup related to file system sync.

CMakeLists.txt

@@ -35,7 +35,7 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/CMakeModules/")
 set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME Core)
 
-add_definitions(-DQS_LOG_LINE_NUMBERS)
+add_definitions(-DQS_LOG_LINE_NUMBERS -DQS_LOG_SEPARATE_THREAD)
 
 include(utils)
 include(CompilerFlags)