Merge branch 'maint'

Merge branch 'maint'

* maint:
  gnupload: moved to gnulib
  sync: gitlog-to-changelog from gnulib upstream
  test defs: backport optimized 'using_gmake' implementation
  tests: unify some tests on "make -n", reducing duplication
  vala: use "$(am__cd) $(srcdir)", not "cd $(srcdir)"

+ Extra edits:

* tests/maken3.test: Carry over (with necessary adjustments) the
code from maken4.test that determines whether $MAKE supports the
special '.MAKE' target.