Merge branch 'maint'

* maint:
  maint: don't use "union" merge driver for NEWS anymore
  build: avoid too greedy rebuilds in the testsuite
  tests: avoid yet another spurious environment influence
  tests: fix a failure in Lex/C++ tests on Mac OS X
  tests: fix a spurious failure due to truncated timestamps
  build: require autoconf 2.69
  build: don't require minimal automake version in AM_INIT_AUTOMAKE

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

diff --combined configure.ac
index 1885836,22a158f..3f55df7
--- 1/configure.ac
--- 2/configure.ac
+++ b/configure.ac
@@@ -15,8 -15,8 +15,8 @@@
  # You should have received a copy of the GNU General Public License
  # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  
- AC_PREREQ([2.68])
+ AC_PREREQ([2.69])
 -AC_INIT([GNU Automake], [1.12.0a], [bug-automake@gnu.org])
 +AC_INIT([GNU Automake], [1.12a], [bug-automake@gnu.org])
  
  AC_CONFIG_SRCDIR([automake.in])
  AC_CONFIG_AUX_DIR([lib])
@@@ -39,7 -39,7 +39,7 @@@ AC_SUBST([am_AUTOUPDATE], ["${AUTOUPDAT
  dnl We call AC_PROG_CC in an unusual way, and only for use in our
  dnl testsuite, so also use 'no-dependencies' and 'no-define' among
  dnl the automake options to avoid bloating and potential problems.
- AM_INIT_AUTOMAKE([1.10a dist-xz filename-length-max=99 color-tests
+ AM_INIT_AUTOMAKE([dist-xz filename-length-max=99 color-tests
                  parallel-tests silent-rules no-define no-dependencies])
  
  # The API version is the base version.  We must guarantee
@@@ -299,7 -299,6 +299,6 @@@ _AM_COMPILER_CAN_FAIL([AC_PROG_FC(dn
    [xlf90 f90 pgf90 pghpf epcf90 g95 gfortran])],
    [FC=false; _AM_SKIP_COMP_TESTS([Fortran])])
  
- # FIXME this won't work as expected until we can assume autoconf 2.69 :-(
  AS_IF([test x"$GFC" = x"yes"], [am_FC_is_GNU=yes], [am_FC_is_GNU=no])
  
  _AM_COMPILER_CAN_FAIL([AC_PROG_F77(dnl