Re: Define a complete rule via autoconf (quoting issue, AC_SUBST)

[Daniel Leidert]

Am Dienstag, den 28.10.2008, 07:50 +0100 schrieb Ralf Wildenhues:
> Hi Daniel,
> 
> * Daniel Leidert wrote on Mon, Oct 27, 2008 at 11:04:34PM CET:
> > 
> > I want to place a rule in several Makefiles. So I thought about putting
> > 
> > @DESKTOP_DATA_RULE@
> > 
> > into every Makefile.am and define the rule via configure.ac. However, I
> > can't get it to work.
> 
> Should be possible with recent Autoconf.  If you also use Automake,
> however, you need to get it to not add
>   DESKTOP_DATA_RULE = @DESKTOP_DATA_RULE@
> 
> into the Makefile.in.  Currently, that is only possible through an
> undocumented Automake macro, _AM_SUBST_NOTMAKE([DESKTOP_DATA_RULE]).
> The intention is to fix that for the next Automake release.
> 
> If you still have problems after this, please show what you tried,
> and what's output, and the error.

I get errors running ./configure. I guess, this is, because of a problem
with the quotation. Doing a simple:

AC_SUBST([DESKTOP_DATA_RULE], [
target: requirements
        @list=...

])

doesn't work. The rerrors are related to the variables contained in the
rule. But I did not find an example, how I need to escape special
characters in the rule (or at least: which characters I need to escape).

> Besides the workarounds already mentioned, other possibilities include
> Automake conditionals.

I now conditionally include a Makefile snippet, which contains the
rules.

> > $(desktop_DATA): $(desktop_in_files:.desktop.in=.desktop)
> >     @list='$<'; for p in $$list; do \
> 
> Please note that using $< outside of inference rules requires GNU make.

The build system already uses some GNU make extensions (especially  the
gnome-doc-utils Makefile snippet requires GNU make), but I try to
minimize its usage. So many thanks for your hints.

But my Makefiles also require it, because the following works, but the
install rules fail:

schemas_DATA = `echo "$(schemas_in_files)" | sed 
's/.schemas.in$$//;$(transform);s/$$/.schemas/'`

Running the install target fails, because the installation rules do not
expand this expression. Instead they try to install "`echo". So I need:

schemas_DATA = $(shell echo "$(schemas_in_files)" | sed 
's/.schemas.in$$//;$(transform);s/$$/.schemas/')

and this works. Is there maybe a solution, which doesn't require GNU
make here?

Regards, Daniel