[PATCH 0/2] Use build/ subdirectory to store build artifacts

Running the test cases cause some pollution of the source tree, which makes
`git status` unhappy and a command such as `git add` would mistakenly add bogus
files to the git tree.

The recommended workaround is to do out-of-tree builds.

We can try to *suggest* or *enforce* it by using the AX_ENABLE_BUILDDIR macro
from the autoconf-archive project which can be found here:
http://www.gnu.org/software/autoconf-archive/ax_enable_builddir.html

That way, if an in-tree build is attempted, the makefiles will instead create a
build/ subdirectory and place all build artifacts there.

Normal out-of-tree builds are not affected, no new build/ directory is
introduced with no changes to the original layout.

Update the .gitignore file to list /build and to stop listing files that are no
longer expected on the source tree (such as *.o, etc.)

While at it, introduce a prequel commit to enable the automake subdir-objects
option, which causes automake 1.14 to print a deprecation warning, and only
affects testsuite/libdejagnu/unit.o so it should be pretty safe.

Thanks,
Filipe

Filipe Brandenburger (2):
  Enable subdir-objects automake option
  Use build/ subdirectory to store build artifacts

 .gitignore               |  12 +-
 ChangeLog                |  18 +++
 Makefile.in              |  69 ++++++----
 aclocal.m4               |   2 +
 configure                | 350 ++++++++++++++++++++++++++++++++++++++++++++++-
 configure.ac             |   4 +-
 m4/ax_configure_args.m4  |  70 ++++++++++
 m4/ax_enable_builddir.m4 | 301 ++++++++++++++++++++++++++++++++++++++++
 8 files changed, 789 insertions(+), 37 deletions(-)
 create mode 100644 m4/ax_configure_args.m4
 create mode 100644 m4/ax_enable_builddir.m4

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2.2.0.rc0.207.ga3a616c