Improve CopyLibs.cmake fix from 7d30537 for nonrecursive cases...

... When the graph of library dependencies is not recursive but complicated,
a combinatorial explosion of paths could make the post-build step not infinite
but very long (80 minutes in one of my experimental refactoring branches!)

cmake-proxies/cmake-modules/CopyLibs.cmake

@@ -116,6 +116,7 @@ function( gather_libs src )
 
    set( libs ${libs} PARENT_SCOPE )
    set( postcmds ${postcmds} PARENT_SCOPE )
+   set( VISITED ${VISITED} PARENT_SCOPE )
 endfunction()
 
 gather_libs( "${SRC}" )