[FYI] {master} Drop support for $(ACLOCAL_M4_SOURCES), it's obsolete

[Stefano Lattarini]

The $(ACLOCAL_M4_SOURCES) variables has been obsolete by a long time,
and basically unused (since at least commit ab57cf28 of 2003-04-24), so
drop any mention of it.

* automake.in (scan_aclocal_m4): Flatly reject any ACLOCAL_M4_SOURCES
definition with a fatal error, rather than just warning about it.
if any deinifn
$(ACLOCAL_M4_SOURCES).  Don't append it to @ac_deps.  This makes such
variable always empty, so there's no need to return it.  Adjust the
signature of this function accordingly, and ...
(handle_configure): ... update this function accordingly.
* NEWS: Update.

Signed-off-by: Stefano Lattarini <address@hidden>
---
 NEWS        |  4 ++++
 automake.in | 19 +++++--------------
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/NEWS b/NEWS
index be3ea37..2b64a1e 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,10 @@ New in 1.14:
 
 * Obsolete and obsolescent features:
 
+  - Support for the long-obsolete variable $(ACLOCAL_M4_SOURCES) has
+    been removed.  It should be safe to simply remove any definition
+    of it you have in your Makefiles.
+
   - Support for the long-obsolete $(INCLUDES) variable has been finally
     removed, in favour of the modern equivalent $(AM_CPPFLAGS).
 
diff --git a/automake.in b/automake.in
index f829ad6..0c06401 100644
--- a/automake.in
+++ b/automake.in
@@ -3877,21 +3877,13 @@ sub scan_aclocal_m4 ()
       $regen_aclocal = $line =~ 'generated automatically by aclocal';
     }
 
-  my @ac_deps = ();
-
-  if (set_seen ('ACLOCAL_M4_SOURCES'))
-    {
-      push (@ac_deps, '$(ACLOCAL_M4_SOURCES)');
-      msg_var ('obsolete', 'ACLOCAL_M4_SOURCES',
-              "'ACLOCAL_M4_SOURCES' is obsolete.\n"
-              . "It should be safe to simply remove it");
-    }
+  reject_var ('ACLOCAL_M4_SOURCES',
+             "'ACLOCAL_M4_SOURCES' is obsolete; just remove it");
 
   # Note that it might be possible that aclocal.m4 doesn't exist but
   # should be auto-generated.  This case probably isn't very
   # important.
-
-  return ($regen_aclocal, @ac_deps);
+  return $regen_aclocal;
 }
 
 
@@ -4007,10 +3999,9 @@ sub handle_configure ($$$@)
   my $colon_infile = ':' . join (':', @inputs);
   $colon_infile = '' if $colon_infile eq ":$makefile.in";
   my @rewritten = rewrite_inputs_into_dependencies ($makefile, @inputs);
-  my ($regen_aclocal_m4, @aclocal_m4_deps) = scan_aclocal_m4;
+  my $regen_aclocal_m4 = scan_aclocal_m4;
   define_pretty_variable ('am__aclocal_m4_deps', TRUE, INTERNAL,
-                         @configure_deps, @aclocal_m4_deps,
-                         '$(top_srcdir)/' . $configure_ac);
+                         @configure_deps, "\$(top_srcdir)/$configure_ac");
   my @configuredeps = ('$(am__aclocal_m4_deps)', '$(CONFIGURE_DEPENDENCIES)');
   push @configuredeps, '$(ACLOCAL_M4)' if -f 'aclocal.m4';
   define_pretty_variable ('am__configure_deps', TRUE, INTERNAL,
-- 
1.8.0.1.409.g252f922