Merge branch 'master' into ng/master

* master:
  tests: avoid a possible failure due to autom4te cache staleness
  tests: fix spurious failure in test on TEXINFO_TEX overriding
  tests: avoid some spurious failures on AIX 7.1

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

diff --cc t/parallel-tests-concurrency.sh
index 448b3bc0de38d6d6ce12bd649bccfd941be4548e,4a70e23f67f3754706bf2070a83320bb177ed541..9c80c2c7bcd10549d108501379d5291ea91f84f0
--- 1/t/parallel-tests-concurrency.sh
--- 2/t/parallel-tests-concurrency.sh
+++ b/t/parallel-tests-concurrency.sh
@@@ -68,11 -89,16 +68,14 @@@ for build in serial parallel; d
  done
  
  cd serial
 -# Do *not* use "make -j1" here; apparently, some make implementations
 -# (e.g., AIX 7.1) interpret it as a synonym of "make -j" :-(
 -$MAKE check &
 +$MAKE -j1 check &
- cd ../parallel
+ cd ..
+ 
+ cd parallel
  $sleep
 -run_make -O -- ${j}4 check
 +run_make -O -- -j4 check
  cd ..
+ 
  # Ensure the tests are really being run in parallel mode: if this is
  # the case, the serial run of the dummy testsuite started above should
  # still be ongoing when the parallel one has terminated.