Jeff King [off-list ref] writes:

quoted

Yes, of course, but as I wrote in my response to Brian, the whole
point of using these replacement implementation macros is so that we
do not have to sprinkle the main code with such #ifdef/#endif, so
I think the code like that is what needs to be corrected ;-)

I'm not sure if I made my point clearly. ...

Sorry, indeed I missed it.  

Using the implementation of precompose_argv() itself as an example,
instead of generic looking some_func(), does help to explain why at
some point we are bound to have some API calls that are compiled on
some platforms and not on others.