I want to generate a list of called functions from source file c

Question

ctags -x --c-kinds=f *.c

will provide me with the functions defined in these C files.

But I want instead just the functions called in these C files.

I could not find this option in ctags, and cscope is only displayed interactively.

How can I get a list of functions called in one or more C files sent to stdout for further connection / filtering?