Re: multiline substitutions

[Bruno Haible]

Hi Ralf,

> The remaining sed script could be replaced by AC_SUBST_FILE instances,
> although you'd need to modify the gnulib sources then.
> 
> In order to address the fairly large config.status startup overhead, an
> alternative would be to just declare the headers AC_CONFIG_FILES, then
> they'd be generated normally after configure has run.

I don't believe these two are good advices for gnulib. Both suggestions
require to put file names into configure.ac or .m4 files. Each time we did
that in the past, it caused *major* trouble that was very hard to get rid of
afterwards. Recall the still unresolved story about AC_LIBOBJ [1] and the
problem of AC_CONFIG_LINKS [2] that caused us so many spurious bug reports
from users who were never running "make distclean"; I believe AC_CONFIG_FILES
has the same problem.

The good use of autoconf and automake that I've learned the hard way is:
+-----------------------------------------------------------------+
| - Use autoconf macros for determining platform dependencies.    |
| - Use Makefile rules (in Makefile.am files) for creating files. |
+-----------------------------------------------------------------+

> > +     (cd $(top_builddir) && ./config.status --file=-) < 
> > $(srcdir)/time.in.h | \

This change is acceptable to me only because it keeps file names out of
configure.ac and *.m4.

Bruno

[1] http://lists.gnu.org/archive/html/bug-automake/2010-05/msg00017.html
[2] http://lists.gnu.org/archive/html/bug-gnulib/2010-04/msg00222.html