Re: timespec_get: port to Ubuntu 23.04

[Bruno Haible]

Hi Paul,

> @@ -12,6 +12,7 @@ AC_DEFUN([gl_FUNC_TIMESPEC_GET],
>    AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
>  
>    AC_REQUIRE([gl_CHECK_FUNC_TIMESPEC_GET])
> +  REPLACE_TIMESPEC_GET=0
>    if test $gl_cv_func_timespec_get != yes; then
>      HAVE_TIMESPEC_GET=0
>      case "$gl_cv_onwards_func_timespec_get" in

This looks strange: gl_FUNC_TIMESPEC_GET already requires gl_TIME_H_DEFAULTS,
which already initializes REPLACE_TIMESPEC_GET:

  REPLACE_TIMESPEC_GET=GNULIB_PORTCHECK; AC_SUBST([REPLACE_TIMESPEC_GET])

and GNULIB_PORTCHECK evaluates to 0 by default in C compilation units.
And the shell code never tests $REPLACE_TIMESPEC_GET against 0, only
against 1.

Is something wrong with the m4/time_h.m4 idioms? What was the recipe to
reproduce a bug here?

Bruno