diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4640db66..78298a53 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,12 +16,15 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${colobot_SOURCE_DIR}/cmake")
 ##
 
 # Global build type
-set(CMAKE_BUILD_TYPE debug)
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
 
 # Global compile flags
 # These are specific to GCC/MinGW; for other compilers, change as necessary
-set(CMAKE_CXX_FLAGS_RELEASE "-O2 -Wall -Wold-style-cast -std=gnu++0x")
-set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_RELEASE "-O2")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 # Asserts can be enabled/disabled regardless of build type
 option(ASSERTS "Enable assert()s" ON)
diff --git a/src/CBot/tests/CBot_console/CMakeLists.txt b/src/CBot/tests/CBot_console/CMakeLists.txt
index 7d9f0340..9f0f2444 100644
--- a/src/CBot/tests/CBot_console/CMakeLists.txt
+++ b/src/CBot/tests/CBot_console/CMakeLists.txt
@@ -3,11 +3,14 @@ cmake_minimum_required(VERSION 2.8)
 project(CBot_console C CXX)
 
 # Build with debugging symbols
-set(CMAKE_BUILD_TYPE debug)
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
 
 # Global compile flags
-set(CMAKE_CXX_FLAGS_RELEASE "-O2 -Wall -Wold-style-cast -std=gnu++0x")
-set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_RELEASE "-O2")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 # Include cmake directory
 SET(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${colobot_SOURCE_DIR}/cmake")
diff --git a/src/common/test/CMakeLists.txt b/src/common/test/CMakeLists.txt
index 08efdb3b..26a31c9b 100644
--- a/src/common/test/CMakeLists.txt
+++ b/src/common/test/CMakeLists.txt
@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 2.8)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall -Wold-style-cast -std=gnu++0x")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 include_directories(
 .
diff --git a/src/graphics/engine/test/CMakeLists.txt b/src/graphics/engine/test/CMakeLists.txt
index 775abe52..46509f4b 100644
--- a/src/graphics/engine/test/CMakeLists.txt
+++ b/src/graphics/engine/test/CMakeLists.txt
@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 2.8)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall -Wold-style-cast -std=gnu++0x")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 set(MODELFILE_TEST_SOURCES
 modelfile_test.cpp
diff --git a/src/graphics/opengl/test/CMakeLists.txt b/src/graphics/opengl/test/CMakeLists.txt
index be33ac6f..154fec84 100644
--- a/src/graphics/opengl/test/CMakeLists.txt
+++ b/src/graphics/opengl/test/CMakeLists.txt
@@ -5,8 +5,11 @@ find_package(SDL REQUIRED)
 find_package(SDL_image REQUIRED)
 find_package(PNG REQUIRED)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-Wall -g -O0 -Wold-style-cast -std=gnu++0x")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 set(ADD_LIBS "")
 
diff --git a/src/math/test/CMakeLists.txt b/src/math/test/CMakeLists.txt
index 5bc9027a..dae40188 100644
--- a/src/math/test/CMakeLists.txt
+++ b/src/math/test/CMakeLists.txt
@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 2.8)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall -Wold-style-cast -std=gnu++0x")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 include_directories(
 .
diff --git a/src/plugins/test/CMakeLists.txt b/src/plugins/test/CMakeLists.txt
index a68de2cc..31b41637 100644
--- a/src/plugins/test/CMakeLists.txt
+++ b/src/plugins/test/CMakeLists.txt
@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 2.8)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-Wall -g -O0 -std=c++11 -rdynamic")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -std=c++11 -rdynamic")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 add_executable(manager_test manager_test.cpp ../../common/logger.cpp ../../common/profile.cpp ../../common/iman.cpp ../pluginmanager.cpp ../pluginloader.cpp)
 
diff --git a/src/sound/plugins/oalsound/CMakeLists.txt b/src/sound/plugins/oalsound/CMakeLists.txt
index 0bc94829..bb7e9ffe 100644
--- a/src/sound/plugins/oalsound/CMakeLists.txt
+++ b/src/sound/plugins/oalsound/CMakeLists.txt
@@ -6,7 +6,8 @@ set(SOURCES
     channel.cpp
 )
 
-SET (CMAKE_CXX_FLAGS "-Wall  -g -std=c++0x -fPIC")
+SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -std=c++0x -fPIC")
+SET (CMAKE_CXX_FLAGS_DEBUG "-g")
 
 include(FindPkgConfig)
 include(FindOpenAL)
diff --git a/src/sound/plugins/oalsound/test/CMakeLists.txt b/src/sound/plugins/oalsound/test/CMakeLists.txt
index f7b165c4..dd208ea1 100644
--- a/src/sound/plugins/oalsound/test/CMakeLists.txt
+++ b/src/sound/plugins/oalsound/test/CMakeLists.txt
@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 2.8)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-Wall -g -O0 -std=c++11 -rdynamic")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -std=c++11 -rdynamic")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 add_executable(plugin_test plugin_test.cpp ../../../../common/iman.cpp ../../../../common/logger.cpp ../../../../plugins/pluginloader.cpp)
 
diff --git a/src/ui/test/CMakeLists.txt b/src/ui/test/CMakeLists.txt
index 7562a043..e411067b 100644
--- a/src/ui/test/CMakeLists.txt
+++ b/src/ui/test/CMakeLists.txt
@@ -1,7 +1,10 @@
 cmake_minimum_required(VERSION 2.8)
 
-set(CMAKE_BUILD_TYPE debug)
-set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall -Wold-style-cast -std=gnu++0x")
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE debug)
+endif(NOT CMAKE_BUILD_TYPE)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wold-style-cast -std=gnu++0x")
+set(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 include_directories(
 .