bug#7988: the manual suggests installing macro files to hard-coded location

[Stefano Lattarini]

On Saturday 05 February 2011, Peter Johansson wrote:
> Hello,
> 
Hello Peter, and sorry for the terrible delay.

> In the manual, 
> http://sources.redhat.com/automake/automake.html#Invoking-aclocal,
> I read about the `--print-ac-dir' option:
> 
> ``Prints the name of the directory that aclocal will search to find
>   third-party .m4 files. When this option is given, normal processing
>   is suppressed. This option can be used by a package to determine
>   where to install a macro file.''
> 
> I find the last sentence a bit strange because to me that sounds like 
> Automake suggests that packagers should install macro files in a 
> hard-coded directory not relative to $(prefix).
>
Yes, this is exactly what it suggests.  Unfortunately, this is currently
the best way to allow aclocal to find the installed third-pary macro file;
for more information see:
 <http://www.gnu.org/software/automake/manual/html_node/Macro-Search-Path.html>

Another viable approach would be to install the third-party macro file
in `$(third-party-prefix)/share/aclocal', and then extend the file
`$(aclocal-prefix)/share/aclocal/dirlist' to list that directory too; but
this would mean *modify* a possibly pre-existing file (and in a hard-coded
location too), and I'm not sure this is a wise move (but maybe might be
worth citing in the documentation anyway... Opinions?)

Finally, note that this problem should be ameliorated once the pending
patches introducing support for the ACLOCAL_PATH environment variable
are merged:
 <http://lists.gnu.org/archive/html/automake-patches/2010-11/msg00089.html>
At that point, a thid-party package providing macro files can install them
into `$(third-party-prefix)/share/aclocal', and then tell the user to
extend the system-wide definition of ACLOCAL_PATH accordingly (somewhat
similarly to what libtool install rules does with `LD_LIBRARY_PATH').

> IIUC that that contradicts the discussion in section "Install to
> Hard-Coded Locations"
>
> http://sources.redhat.com/automake/automake.html#Hard_002dCoded-Install-Paths
> 
> Cheers,
> Peter
> 

Thanks,
   Stefano