Append CXXFLAGS env. variable to CMAKE_CXX_FLAGS

This facilitates address sanitizer builds via env. variable.

Change-Id: I69fc9a5782ca80d7bdbf2b1ec0c89cccc4a5ca11

CMakeLists.txt

@@ -129,8 +129,9 @@ add_definitions(-DLITTLEENDIAN_CPU=1)
 #
 # Linux Compiler options
 #
-set(CMAKE_CXX_FLAGS "-std=c++11 ")
+set(CMAKE_CXX_FLAGS "$ENV{CXXFLAGS}")
 
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fexceptions")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-rtti")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-math-errno")