Merge branch 'maint' into yacc-work

Merge branch 'maint' into yacc-work

* maint:
  * THANKS (Daniel Richard G.): Update e-mail address.
  java: avoid compilation errors when CLASSPATH is empty
  parallel-tests: no more spurious successes for FreeBSD make
  hacking: we now require autoconf 2.68
  test defs: more environment cleanup
  tests: fix spurious failure with Solaris make
  maintcheck: fix maintainer-check failures, both real and spurious
  docs: how to use '-I' option in AM_CPPFLAGS for best VPATH support
  tests: relax a test on amhello examples to cater to Solaris tar
  docs: add references between the 2 sections on java support
  Sync auxiliary files from upstream.