Automake 1.15 + subdir-objects using $(top_srcdir) in *_SOURCES

[Tom Ghyselinck]

Hi all,

I just upgraded to automake-1.15.

I got a warning about future incompatibilities:
    src/Makefile.am:205: warning: source file 
'StackControllers/AbstractController.cpp' is in a subdirectory,
    src/Makefile.am:205: 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.

We use "<subdir>/<source_file>.cpp" in some "*_SOURCES" entries in our
"Makefile.am" files.

Since I don't like warnings, I followed the suggestion and added the "s
ubdir-objects" option in our configure.ac.

Now, in one of our Makefile.am we are using
    gtest_SOURCES = $(top_srcdir)/src/globaloptions.cpp ...

We build our project in /tmp/build.
When trying to execute "make clean" for our project, we get the error:
    Making clean in testing
    make[2]: Entering directory '/tmp/build/src/testing'
    Makefile:1193: /path/to/source/src/.deps/gtest-globaloptions.Po: No such 
file or directory
    make[2]: *** No rule to make target 
'/path/to/source/src/.deps/gtest-globaloptions.Po'.  Stop.
    make[2]: Leaving directory '/tmp/build/src/testing'
    Makefile:1513: recipe for target 'clean-recursive' failed

Is this a known issue?
Or is it incorrect to use "$(top_srcdir)" in the "*_SOURCES" directive
when using the "subdirs-objects" option?

We would like to keep using the "$(top_srcdir)" since the subdirs where
the Makefile.am using this resides may move around in the project
directory tree.

Can anyone explain what is going wrong or how we should update this to
keep this working?

Thank you in advance!

With best regards,
Tom.

-- 
Tom Ghyselinck <address@hidden>
Excentis N.V.