mapi: fix out-of-tree build dependencies

mapi: fix out-of-tree build dependencies

We shouldn't be using wildcard here in the first place, but changing that
is some effort. As it stands, make -p confirms that glapi_gen_mapi_deps only
contains mapi_abi.py when building outside the Mesa tree.

As a result, only some of the tables were updated when XML files change, but
not the tables for shared glapi. This change ensures that we pick up the
XML files and scripts from the source tree as dependencies also for shared
glapi.

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>