automake warnings

[John Ralls]

> On Feb 5, 2015, at 2:21 PM, Alex Aycinena <alex.aycinena at gmail.com> wrote:
> 
> When I run './autogen.sh' on my Fedora 21 machine, I get the following:
> 
> Makefile.am:10: warning: source file 'util/guile.c' is in a subdirectory,
> Makefile.am:10: but option 'subdir-objects' is disabled
> automake: warning: possible forward-incompatibility.
> automake: At least a source file is in a subdirectory, but the
> 'subdir-objects'
> automake: automake option hasn't been enabled.  For now, the corresponding
> output
> automake: object file(s) will be placed in the top-level directory.
> However,
> automake: this behaviour will change in future Automake versions: they will
> automake: unconditionally cause object files to be placed in the same
> subdirectory
> automake: of the corresponding sources.
> automake: You are advised to start using 'subdir-objects' option throughout
> your
> automake: project, to avoid future incompatibilities.
> 
> followed by many messages like the following:
> 
> src/app-utils/Makefile.am:40: warning: source file
> 'calculation/expression_parser.c' is in a subdirectory,
> src/app-utils/Makefile.am:40: but option 'subdir-objects' is disabled
> 
> This is between the lines:
> 
> Running automake --add-missing --gnu --warnings=no-portability  ...
> 
> and
> 
> Running autoconf ...
> 
> configure, make and make install all seem to work fine.On my Fedora 20
> machine I don't see these warnings.
> 
> I don't know if this is because of something different in my environment
> between the two or because of the versions of the tools in the two machines.
> 
> Can someone give me feedback? I believe, Greet, you use Fedora also. Do you
> see this as well?
> 

Alex,

There’s actually an explanation in configure.ac:
# Initialize automake -- make sure we have at least version 1.9 Note:
# Automake 1.14 issues a ton of warnings about subdir-objects, which
# will become the default in automake 2.0; unfortunately this option
# is broken and prevents building without passing
# --disable-dependency-tracking to configure, which make-distcheck
# doesn't do. See
# http://lists.gnu.org/archive/html/automake/2014-04/msg00002.html and
# http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13928 for details.
# In the meantime the best option is to use Automake 1.13 or earlier.

Regards,
John Ralls