[Automake-NG] [FYI] [ng] tags: drop support for pre-5.6 exuberant ctags

[Stefano Lattarini]

Exuberant Ctags before that version (release in 2006) could
fail to create TAGS files when no files are supplied, despite
any '--etags-include' option.  This required the addition of
a workaround ...

* lib/am/tags.am (tags-am): ... here, which can now be removed.

Signed-off-by: Stefano Lattarini <address@hidden>
---
 lib/am/tags.am | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/lib/am/tags.am b/lib/am/tags.am
index ad4e8ba..1d0d1ed 100644
--- a/lib/am/tags.am
+++ b/lib/am/tags.am
@@ -47,17 +47,12 @@ tags-am: $(TAGS_DEPENDENCIES) $(am.tags.files)
 ## We use the positional parameters to build the subdir list with
 ## absolute names, without the need to worry about white space in `pwd`.
        set x; \
-## Exuberant Ctags wants --etags-include,
-## GNU Etags             --include
-## Furthermore Exuberant Ctags 5.5.4 fails to create TAGS files
-## when no files are supplied, despite any --etags-include option.
-## A workaround is to pass '.' as a file.  This is what $empty_fix is for.
+## Exuberant Ctags wants --etags-include.
+##       GNU Etags wants --include.
 ?SUBDIRS?      if ($(ETAGS) --etags-include --version) >/dev/null 2>&1; then \
 ?SUBDIRS?        include_option=--etags-include; \
-?SUBDIRS?        empty_fix=.; \
 ?SUBDIRS?      else \
 ?SUBDIRS?        include_option=--include; \
-?SUBDIRS?        empty_fix=; \
 ?SUBDIRS?      fi; \
 ?SUBDIRS?      list='$(SUBDIRS)'; for subdir in $$list; do \
 ## Do nothing if we're trying to look in '.'.
@@ -70,12 +65,10 @@ tags-am: $(TAGS_DEPENDENCIES) $(am.tags.files)
 ## Remove the 'x' we added first:
        shift; \
 ## Make sure we have something to run etags on.
-       unique='$(am.tags.files.unique)'; \
-       if test -z "$(ETAGS_ARGS)$$*$$unique"; then :; else \
-         test -n "$$unique" || unique=$$empty_fix; \
+       test -n "$(ETAGS_ARGS)$$*$(am.tags.files.unique)" || { \
          $(ETAGS) $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
-           ${1+"$$@"} $$unique; \
-       fi
+           ${1+"$$@"} $(am.tags.files.unique); \
+       }
 
 
 ## --------------- ##
-- 
1.7.12.rc0