automake: rework patch; only skip when the directories does not exist, this preserves error cases like missing access permissions

SVN-Revision: 24427

tools/automake/patches/100-aclocal-skip-not-existing-directories.patch

@@ -1,12 +1,15 @@
 --- a/aclocal.in
 +++ b/aclocal.in
-@@ -311,7 +311,8 @@ sub scan_m4_dirs ($@)
+@@ -309,6 +309,12 @@ sub scan_m4_dirs ($@)
+ 
+   foreach my $m4dir (@dirlist)
      {
-       if (! opendir (DIR, $m4dir))
- 	{
--	  fatal "couldn't open directory `$m4dir': $!";
++      if (! -d $m4dir)
++      {
 +        msg ('override', "warning: skipping not existing directory `$m4dir'");
 +        next;
- 	}
- 
-       # We reverse the directory contents so that foo2.m4 gets
++      }
++
+       if (! opendir (DIR, $m4dir))
+ 	{
+ 	  fatal "couldn't open directory `$m4dir': $!";