Merge remote-tracking branch 'origin/maint'

* origin/maint:
  maint: post-release administrivia
  version 3.0.4
  gnulib: update
  build: re-enable compiler warnings, and fix them
  tests: c++: fix a C++03 conformance issue
  tests: fix a title
  c++: reserve 200 slots in the parser's stack
  tests: be more robust to unrecognized synclines, and try to recognize xlc
  tests: fix C++ conformance
  build: fix some warnings
  build: avoid infinite recursions on include_next

src/ielr.c

@@ -1102,7 +1102,10 @@ ielr (void)
     else if (STREQ (type, "canonical-lr"))
       lr_type = LR_TYPE__CANONICAL_LR;
     else
-      aver (false);
+      {
+        aver (false);
+        abort ();
+      }
     free (type);
   }