[CMake] Elegant solution for preprocessing a linker script?

[Michael Weise]

Hello,

I'm looking for a way to preprocess a linker script.

After (unsuccessfully) trying add_custom_command() I found this
explanation and a workaround:
http://www.mail-archive.com/cmake@cmake.org/msg16496.html


It uses an intermediate dependency "dummy.c" in the source list of
the executable, which forces the custom command to be executed:

----
add_executable(cmake_test ${CMAKE_CURRENT_BINARY_DIR}/dummy.c)

add_custom_command(
  OUTPUT  ${CMAKE_CURRENT_BINARY_DIR}/dummy.c
  COMMAND ${CMAKE_C_COMPILER} -E ${CMAKE_CURRENT_SOURCE_DIR}/api.lds.S
                              -P -o ${CMAKE_CURRENT_BINARY_DIR}/api.lds 
  COMMAND echo "/* this file is (almost) empty */"
               > ${CMAKE_CURRENT_BINARY_DIR}/dummy.c
  MAIN_DEPENDENCY ${CMAKE_CURRENT_SOURCE_DIR}/api.lds.S )

set(CMAKE_EXE_LINKER_FLAGS "-T api.lds")
----

While this is actually working, I find the approach somehow "dirty".
Is there a more elegant solution without the dummy.c file?

Best Regards
Michael