build: declare real built files

build: declare real built files

When runnig the `make dist` target from a clean tree, it fails because
if could not find the copied files from codecparsers submodule.

They weren't copied because they weren't declared as built sources.

This patch removes the stamp mechanism and use the actual file list to copy
as the built sources. Also it fixes the duplication of the parser files.

Signed-off-by: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>
https://bugzilla.gnome.org/show_bug.cgi?id=755525