bug#52500: misleading description of %reldir%

[Bruno Haible]

Hi,

The documentation
https://www.gnu.org/software/automake/manual/automake.html#Include
says:

  "A special feature is that if the fragment is in the same directory
   as the base Makefile.am (i.e., %reldir% is .), then %reldir% and
   %canon_reldir% will expand to the empty string as well as eat, if
   present, a following slash or underscore respectively."

IMO, this paragraph implies that if the fragment is in the same directory
as the base Makefile.am
  - %reldir% without a following slash expands to empty,
  - %canon_reldir% without a following underscore expands to empty.
But this is not the case. (And if it were, the %reldir% and
%canon_reldir% feature would be unusable.) In fact,
%reldir% without a following slash expands to a dot, and
%canon_reldir% without a following underscore expands to an underscore.

Suggested new text:

   A special feature is that if the fragment is in the same directory
   as the base Makefile.am (i.e., %reldir% is .), then
     - %reldir% together with a following slash will expand to empty,
     - %canon_reldir% together with a following underscore will expand
       to empty as well.

Bruno