warns: enable category 'obsolete' by default

No surprise that our users were bitten by backward-incompatible changes
especially hard: the warnings in the 'obsolete' category, that might
have informed them of the upcoming incompatibilities, and help them to
prepare for the transition, where not enabled by default!

* NEWS, doc/automake.texi: Update.
* lib/Automake/ChannelDefs.pm: Enable warnings in the category 'obsolete'
by default.
* t/warnings-obsolete-default.sh: New test.
* t/list-of-tests.mk: Add it.
* t/backcompat.sh: Use 'configure.ac' rather than 'configure.in' as
autoconf input file, to avoid spurious aclocal errors.
* t/backcompat2.sh: Likewise.
* t/backcompat3.sh: Likewise.
* t/backcompat5.sh: Add '-Wno-obsolete' when invoking aclocal.  Adjust
heading comments.
* t/backcompat6.sh: Likewise.
* t/cygnus-imply-foreign.sh:  Add '-Wno-obsolete' when invoking automake.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/t/backcompat6.sh b/t/backcompat6.sh
index 30403dd75..ee86e3644 100755
--- a/t/backcompat6.sh
+++ b/t/backcompat6.sh
@@ -15,7 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Backward-compatibility test: try to build and distribute a package
-# using obsoleted forms of AC_INIT, AM_INIT_AUTOMAKE and AC_OUTPUT.
+# using obsoleted forms of AC_INIT, AM_INIT_AUTOMAKE and AC_OUTPUT,
+# and 'configure.in' as autconf input file.
 # This script can also serve as mild stress-testing for Automake.
 # See also the similar test 'backcompat5.sh'.
 
@@ -77,7 +78,7 @@ int main (void)
 }
 END
 
-$ACLOCAL
+$ACLOCAL -Wno-obsolete
 $AUTOMAKE -Wno-obsolete --add-missing
 $AUTOCONF