Fix to make --avoid=dummy work

[Simon Josefsson]

I have installed this -- autobuild is a shell-script-only project but
it uses gnulib for the 'autobuild.m4' file.

/Simon

? MODULES.html
Index: ChangeLog
===================================================================
RCS file: /sources/gnulib/gnulib/ChangeLog,v
retrieving revision 1.1553
diff -u -p -r1.1553 ChangeLog
--- ChangeLog   12 Apr 2007 11:19:39 -0000      1.1553
+++ ChangeLog   12 Apr 2007 11:56:29 -0000
@@ -1,5 +1,9 @@
 2007-04-12  Simon Josefsson  <address@hidden>
 
+       * gnulib-tool (func_modules_add_dummy): Respect --avoid=dummy.
+
+2007-04-12  Simon Josefsson  <address@hidden>
+
        * modules/autobuild: New module.
 
        * m4/autobuild.m4: New file.
Index: gnulib-tool
===================================================================
RCS file: /sources/gnulib/gnulib/gnulib-tool,v
retrieving revision 1.230
diff -u -p -r1.230 gnulib-tool
--- gnulib-tool 3 Apr 2007 23:27:57 -0000       1.230
+++ gnulib-tool 12 Apr 2007 11:56:30 -0000
@@ -1175,7 +1175,9 @@ ba
   done
   # Add the dummy module, to make sure the library will be non-empty.
   if test -z "$have_lib_SOURCES"; then
-    func_append modules " dummy"
+    if func_acceptable "dummy"; then
+      func_append modules " dummy"
+    fi
   fi
 }