diff --git a/cmake/modules/AddCompilerFlags.cmake b/cmake/modules/AddCompilerFlags.cmake
--- a/cmake/modules/AddCompilerFlags.cmake
+++ b/cmake/modules/AddCompilerFlags.cmake
@@ -44,6 +44,29 @@
 	endforeach()
 endmacro()
 
+function(add_cxx_compiler_flag_with_fallback TARGET_VAR FLAG FALLBACK)
+	# Remove the fallback flag if it exists, so that the main flag will override
+	# it if it was previously added.
+	string(REGEX REPLACE "${FALLBACK}( |$)" "" ${TARGET_VAR} "${${TARGET_VAR}}")
+	
+	set(TMP_FLAG ${FLAG})
+	unset(FLAG_IS_SUPPORTED CACHE)
+	CHECK_CXX_COMPILER_FLAG(${TMP_FLAG} FLAG_IS_SUPPORTED)
+	if(NOT FLAG_IS_SUPPORTED)
+		set(TMP_FLAG ${FALLBACK})
+		unset(FLAG_IS_SUPPORTED CACHE)
+		CHECK_CXX_COMPILER_FLAG(${TMP_FLAG} FLAG_IS_SUPPORTED)
+	endif()
+	
+	if(FLAG_IS_SUPPORTED)
+		if(NOT "${${TARGET_VAR}}" STREQUAL "")
+			string(APPEND ${TARGET_VAR} " ")
+		endif()
+		string(APPEND ${TARGET_VAR} "${TMP_FLAG}")
+		set(${TARGET_VAR} ${${TARGET_VAR}} PARENT_SCOPE)
+	endif()
+endfunction()
+
 # Note that CMake does not provide any facility to check that a linker flag is
 # supported by the compiler, but most linker will just drop any unsupported flag
 # (eventually with a warning).
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -24,6 +24,18 @@
 include(AddCompilerFlags)
 remove_compiler_flags(-DNDEBUG)
 
+# Overrides the flags for the Debug build type
+# Prefer -g3, defaults to -g if unavailable
+add_cxx_compiler_flag_with_fallback(DEBUG_G_CXX_FLAG -g3 -g)
+
+# Prefer -Og, defaults to -O0 if unavailable
+add_cxx_compiler_flag_with_fallback(DEBUG_O_CXX_FLAG -Og -O0)
+
+set(CMAKE_C_FLAGS_DEBUG "${DEFAULT_G_C_FLAG} ${DEFAULT_O_C_FLAG}")
+set(CMAKE_CXX_FLAGS_DEBUG "${DEBUG_G_CXX_FLAG} ${DEBUG_O_CXX_FLAG}")
+# Define the debugging symbols DEBUG and DEBUG_LOCKORDER
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DDEBUG -DDEBUG_LOCKORDER")
+
 # Ensure that WINDRES_PREPROC is enabled when using windres.
 if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
 	list(APPEND CMAKE_RC_FLAGS "-DWINDRES_PREPROC")