Merge branch 'master' into ng/master

Merge branch 'master' into ng/master

* master: (41 commits)
  typofix: in comments in 't/ax/test-lib.sh'
  style: call perl functions 'like_this()', not '&like_this()'
  tests on TAP: don't run the driver with perl unconditionally
  typofix: in comments in 'automake.in'
  tests: remove obsolete (and now wrong) comment
  typofix: in diagnostic in test 't/tap-realtime.sh'
  maint: use more perl subroutines prototypes in the automake script
  build: auto-generate perl subroutines prototypes for automake and aclocal
  refactor: rip module Automake::Language out of automake script
  automake: fix reference to relevant tests in comments
  NEWS: we no longer plan to drop $(INCLUDES) support in next major version
  NEWS: IRIX is still supported; only SGI depmode no longer is
  NEWS: IRIX is still supported; only SGI C compiler depcomp no longer is
  coverage: split info files are not installed nor distributed
  maint: version bump after beta release 1.13.1b
  NEWS: typofix
  release: beta release 1.13.1b (will become 1.13.2)
  docs: '.txi' and '.texinfo' extensions are deprecated
  NEWS: document recent documentation improvements
  docs: more precise cross reference
  ...

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