How to add in a CMake project a global file extension (*.pde) to GCC which is treated like C++ code

Question

I have a very simple CMake script. Unfortunately, the project uses a *.pde file which is plain C++ or C code.

CMake is working with any file ending, but I get a comp

Answer 1

You should be able to use set_source_files_properties along with the LANGUAGE property to mark the file(s) as C++ sources:

set_source_files_properties(${TheFiles} PROPERTIES LANGUAGE CXX)

As @steveire pointed out in his own answer, this bug will require something like the following workaround:

set_source_files_properties(${TheFiles} PROPERTIES LANGUAGE CXX)
if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
  add_definitions("-x c++")
endif()