The gnat package now depends on gnat-7, meaning that gnat-7 is the
default Ada compiler in the unstable distribution.
Each source package building an Ada library requires a source+binary
upload with new ALI and SO versions (source-only uploads are not
allowed in the NEW queue).
Each source package depending on an Ada library requires a source
upload with an updated -dev build-dependency, once the dependency has
passed through the NEW queue.
Feel free to contact me for advice, review and/or upload sponsorship.