Merge branch 'next'

* next:
  fix, always leave at least an [EXAMPLES] section behind in a .h2m
  chore, don't list built fmt-special.c as EXTRA_SOURCE
  minor, don't use GNU make patterns in test/, use suffixes instead
  minor, don't use GNU make patterns in lib/, use suffixes instead
  minor, don't use GNU make patterns in src/, use suffixes instead
  fix, PEBKAC, follow autoconf advice and don't use variables in VPATH
  minor, don't use GNU make patterns, use suffix rules instead
  chore, adapt info and man generators in info/ to -clo.ggo -> .ggo change
  chore, generate .x and .xh out of .ggo
  minor, use suffix th2m for texi sources that will be conv'd by texi2h2m.sh
  hygiene, avoid double listing of BUILT_SOURCES in EXTRA_DIST
  chore, PEBKAC, properly embrace conditional substs in texi2h2m.sh sed script