build: rework cloc recipe

build: rework cloc recipe

We are going to make other modifications to the cloc recipe, so this
patch prepare make those modification easier.

We replace the Makefile meta programming by just a shell script which
should be easier to read and is actually faster to execute.

Instead of looking for files in "$(BASEDIR)", we use "." which is give
the same result overall. We also avoid the need for a temporary file
as cloc can read the list of files from stdin.

No change intended to the output of `cloc`.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>