diff --git a/CMakeLists.txt b/CMakeLists.txt
index 83dac35d..262fd1dd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,21 +35,28 @@ add_definitions(
 
 set(CMAKE_CXX_STANDARD 11)
 
-#SET(CMAKE_BUILD_TYPE Debug)
-set(CMAKE_BUILD_TYPE RelWithDebInfo)
+if(NOT DEFINED CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE RelWithDebInfo)
+endif()
 
 ## flags for standard library
 #set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libstdc++")
 SET(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules")
 
 if(WIN32)
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Ox /Ot /MT")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MT")
 else(WIN32)
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -O3 -pthread")
-	#set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -O0 -pthread")
-	#set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -O0")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pthread")
 endif(WIN32)
 
+if (NOT "${CMAKE_BUILD_TYPE}" MATCHES Debug)
+        if(WIN32)
+	        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Ox /Ot")
+        else(WIN32)
+	        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
+        endif(WIN32)
+endif()
+
 #if(NOT WIN32)
 #    add_definitions(-DHAVE_CONFIG_H)
     if(APPLE)