Merge remote-tracking branch 'origin/maint'

* origin/maint:
  glr: more assertions
  glr: shorten scopes
  glr: formatting changes
  glr: better use of tracing macros
  examples: improve the output of the "variant" example
  variant: remove useless assertion
  tests: remove stray debugging traces
  tests: do not use grep -q
  build: don't require flex for ordinary builds
  maint: update .gitignore
  build: port to pre-5.8.7 perl
  tests: minor change to make it easier to test other skeletons
  uniqstr: fix assertion

src/uniqstr.c

@@ -77,7 +77,8 @@ uniqstr_vsprintf (char const *format, ...)
 void
 uniqstr_assert (char const *str)
 {
-  if (!hash_lookup (uniqstrs_table, str))
+  uniqstr *s = hash_lookup (uniqstrs_table, str);
+  if (!s || s != (uniqstr *)str)
     {
       error (0, 0,
              "not a uniqstr: %s", quotearg (str));