deps.mk does not exist in 2.4.3 tarball

[brook-milligan]

src/Makevars states the following prior to a rule to make deps.mk:

# This file is available only during development.
# For the tarball, we create an empty file.

However, the tarball for release 2.4.3 does not contain the file deps.mk. Consequently, compiling fails on a Mac (15.3.1, Xcode 16.1) because deps.mk does not exist.

The release process should enforce creation of this file, or make should unconditionally create it.