Merge branch 'next'

* next:
  fix, PEBKAC, make dukas' --guess option work on file names that look *almost* like the real thing
  minor, use the result object's oflags in make_utectx() when ...
  minor, have creat_hdr() set the UO_TRUNC flag, ...
  Revert "minor, don't munmap() the map to the file's header in cache_hdr() just because none of the checking works"
  minor, don't munmap() the map to the file's header in cache_hdr() just because none of the checking works
  minor, rewrite creat_hdr() to return an error status (-1 if error, 0 if not)
  minor, adapt ute-mux to changed ute_extend() signature
  cosmetics, include stdbool.h in utefile-private.h as we're using `bool' in signatures
  minor, turn ute_extend() into int returner, -1 indicating error
  minor, turn __fwr_trunc() and ute_trunc() to int returners, -1 indicating error
  cosmetics, obey compiler warnings
  hygiene, mash up array pointers and UNUSED flag properly
  chore, update m4 macro pack for compiler goodies