[cpp] Use -Wnonportable-include-path for CMake.

CMakeLists.txt

@@ -6,8 +6,8 @@ if(MSVC)
 	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
 	set (CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS}")
 else()
-	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -pedantic -Wshadow -std=c89")
-	set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wnon-virtual-dtor -pedantic -Wshadow -std=c++03 -fno-exceptions -fno-rtti")
+	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -pedantic -Wnonportable-include-path -Wshadow -std=c89")
+	set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wnon-virtual-dtor -pedantic -Wnonportable-include-path -Wshadow -std=c++03 -fno-exceptions -fno-rtti")
 endif()
 
 set(CMAKE_INSTALL_PREFIX "./")