Merge branch 'next'

* next:
  fix, hygiene, do not include logger.h and dccp.h in main unserding.h
  fix, PEBKAC, include unistd.h in ud-meta so close() is declared
  chore, migrate umod-example and strat-example to including either uterus/uterus.h or uterus.h
  chore, migrate unsermon to including either uterus/uterus.h or uterus.h
  minor, check for uterus using PKG_CHECK_MODULES_HEADERS
  minor, update sxe-aux.m4 to include PKG_CHECK_MODULES_HEADERS macro