Use -std=gnu++0x instead of -std=c++0x

Bluez uses the non standard "typeof" instead of "__typeof__" in bluetooth.h.
Both GCC and Clang reject that with std=c++0x but accept it with gnu++0x.

CMakeLists.txt

@@ -552,7 +552,7 @@ option(UNITTESTS "Build unitests" OFF)
 ########################################
 # Start compiling our code
 #
-add_definitions(-std=c++0x)
+add_definitions(-std=gnu++0x)
 add_subdirectory(Source)