Re: use of AC_SUBST

[Bruno Haible]

Hi Jim,

> > Likewise with LIB_GETHRXTIME. How about this proposed fix?
> 
> Good catch.

Patch applied.

> However, please make these two lines adjacent:
> (pulling the AC_SUBST "up")
> ...
> I nearly moved the AC_SUBST lines in the changes I made recently,
> but opted not to: I didn't want to mix bug-fix and clean-up fixes.

You didn't want to mix bug fix and cleanup changes on Thursday, so you cannot
expect me to do this today :-)

> Since AC_SUBST can be used anywhere, it's slightly more
> maintainer-friendly to keep these two references to LIB_GETHRXTIME close.
>     LIB_GETHRXTIME=
>     AC_SUBST([LIB_GETHRXTIME])

I disagree. The traditional way to use AC_SUBST is to initialize the variable,
then compute its value, and finally do AC_SUBST of the variable. This coding
style has the advantage that, as a maintainer, when you search for assignments
to the variable, the possible locations of such assignments are limited. In
other words, the initialization and the AC_SUBST act as an opening and closing
brace, respectively.

Yes, for the variables initialized in gl_XYZXYZ_H_DEFAULTS macros, the
assignments can be anywhere. That's a different coding style, and it's harder
to maintain, because each time you search for an assigment, you have to grep
multiple files. This style should IMO not be extended to other areas where it
is not needed.

Bruno