On 2021-12-06 13:49, Stefan Sperling wrote:
> Taking a closer look at this, the FreeBSD port uses a #define to
> work around this:
> https://cgit.freebsd.org/ports/plain/devel/got/files/openbsd-compat/openbsd-compat.h
> 
> /* void -> int */
> #define closefrom(fd)			(closefrom(fd), 0)

libbsd doesn't do this.
https://cgit.freedesktop.org/libbsd/tree/src/closefrom.c
 
> Would this approach work for -portable?

Portable can skip closefrom check in AC_REPLACE_FUNCS and build it
unconditially (AC_LIBOBJ).