[CMake] Top level directory with component install

[Daniel Nelson]

I am using CPACK_ARCHIVE_COMPONENT_INSTALL to create separate tar files
for each component, but when I enable it I no longer have a top level
directory in the tar.

For example, if archive component install is off then the tar files
contains files with paths like foobar-1.2.3-Linux-x86_64/bin/foobar, but
with component install on the paths are just bin/foobar.  I tried
turning CPACK_INCLUDE_TOPLEVEL_DIRECTORY on but it doesn't seem to help.
Is this behavior on purpose and if so is it possible to change?
--
Daniel