preparing for a new release

[Jim Meyering]

Karl has made quite a few improvements, so I'm preparing to make a new
release. But first, I wanted to make the tests pass reliably also when
running them in parallel (the only way I run them, because otherwise,
they take way too long). I run a command like this:

make check AM_TESTSUITE_MAKE="make -j$(( 2*$(nproc) + 1 ))"

That evoked a surprising number of test failures. Note that these are
nondeterministic and depend on the amount of parallelism. All tests
may pass consistently on a system with 2 cores, yet some will fail
every time when nproc prints at least 6.

I've fixed a few of these failures, but here is still at least one
that I have not fixed: t/txinfo-no-clutter. In this case, running it
with no parallelism and by itself passes:
  make -k check TESTS='t/txinfo-no-clutter'
Yet running it with parallel make fails (I'm using make-4.3.90 built
from git, in case it matters):
  make -k check TESTS='t/txinfo-no-clutter' AM_TESTSUITE_MAKE="make
-j$(( 2*$(nproc) + 1 ))"

Not sure I'll work more on this today, so sharing: The attached log
shows that this fails when building that test's final "all" rule,
often because a .dvi file could not be found:

) localization,mv: cannot stat 'bar.dvi': No such file or directory

I've attached the four commits I'm about to push as well as that
individual testsuite.log, in case someone wants to help accelerate the
process.

0001-tests-avoid-failures-due-to-missing-ar-lib.patch
Description: Binary data

0002-tests-accommodate-an-ac_aux_dir-of-.-or.patch
Description: Binary data

0003-doc-fix-quoting-in-suggested-parallel-test-invocatio.patch
Description: Binary data

0004-tests-protect-against-parallel-false-failure.patch
Description: Binary data

test-suite.log
Description: Binary data