if I add a number of sources to a target, ie:

   target_sources(  ${TARGET_NAME_ELF}   .. list of about 100 source files ... )

How can I get the list of source files added to that ELF?

I need to write that list to a file so that I can do other processing on the source files and that needs to be done external to CMAKE

sort of like:

   file( WRITE  SOMEFILE.txt get_target_sources( ${TARGET_NAME_ELF} ) )