tests/Makefile.am:14: but option 'subdir-objects' is disabled

[sunweaver]

[...]
tests/Makefile.am:14: warning: source file '$(GTEST_SOURCE)/src/gtest-all.cc' is in a subdirectory,
tests/Makefile.am:14: but option 'subdir-objects' is disabled
automake: warning: possible forward-incompatibility.
automake: At least a source file is in a subdirectory, but the 'subdir-objects'
automake: automake option hasn't been enabled.  For now, the corresponding output
automake: object file(s) will be placed in the top-level directory.  However,
automake: this behaviour will change in future Automake versions: they will
automake: unconditionally cause object files to be placed in the same subdirectory
automake: of the corresponding sources.
automake: You are advised to start using 'subdir-objects' option throughout your
automake: project, to avoid future incompatibilities.
tests/Makefile.am:14: warning: source file '$(GTEST_SOURCE)/src/gtest_main.cc' is in a subdirectory,
tests/Makefile.am:14: but option 'subdir-objects' is disabled
tests/Makefile.am:85: warning: source file '$(top_builddir)/common/indicator-messages-service.c' is in a subdirectory,
tests/Makefile.am:85: but option 'subdir-objects' is disabled
tests/Makefile.am:85: warning: source file '$(top_srcdir)/src/gactionmuxer.c' is in a subdirectory,
tests/Makefile.am:85: but option 'subdir-objects' is disabled
parallel-tests: installing './test-driver'
[...]

[sunweaver]

Irrelevant now that we have moved to CMake.