Index: gap-4r6p5/cnf/gac.in
===================================================================
--- gap-4r6p5.orig/cnf/gac.in	2013-07-29 15:21:28.260353905 +0200
+++ gap-4r6p5/cnf/gac.in	2013-07-29 15:23:41.274367698 +0200
@@ -449,6 +449,7 @@
         c_link ${output} "${objects}"
 
     else
+        if [ "X${output}" = "X" ]; then output="${name}.so"; fi
         c_link_dyn ${output} "${objects}"
     fi
     
