Re: [RFC PATCH] Makefile: create externcheck target

> On Thu, Oct 08, 2020 at 11:32:03AM +0200, Johannes Schindelin wrote:
> > P.S.: I am not really certain that the `\s` is portable, I do not see any
> > mention of it in
> > https://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_03
> > and would therefore expect BSD sed not to handle this correctly.
>
> I've run a varation of this on MacOS's sed before and it works.
> Unfortunately, I don't have access to a MacOS machine anymore so I can't
> 100% confirm it.
>
> > In any
> > case, the `-i` is _not_ portable, as BSD sed takes a mandatory argument
> > (see
> > https://stackoverflow.com/questions/5694228/sed-in-place-flag-that-works-both-on-mac-bsd-and-linux
> > for more details).
>
> This was the main reason why I sent it out as an RFC (although I forgot
> to mention it in the commit message, whoops). Perhaps we could write
> this as
>
> 	externcheck: $(filter-out $(THIRD_PARTY_SOURCES),$(filter %.c %.h,$(shell $(FIND_SOURCE_FILES))))
> 		sed -i.bak 's/^\(\s*\)extern \([^(]*([^*]\)/\1\2/' $^
> 		$(RM) $(addsuffix .bak,$^)
>
> instead? I think that since this is a developer target, we can probably
> call this portable enough.